How is graphics RAM different from system RAM?











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I know that a GPU and a CPU are fundamentally different things and why they both suck at doing the other's job. But what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards.



As I understand it, they're both just different types of DRAM, but it seems to me that the differences could be abstracted away by the memory controller baked into CPU and GPU silicon. The current standard for system RAM is DDR4, but video cards were using GDDR4 for years before DDR4 became a thing for desktops. Video cards are now shipping with HBM RAM (GDDR5?), which is faster than DDR4 system memory.



Why aren't we using the same kind of RAM for both? What makes them different?










share|improve this question






















  • I do want to point out that in some cases the system RAM and graphics RAM are exactly the same. Typically found in lower end computers, the BIOS assigns an amount of the system's RAM to the GPU to use as graphics memory. This amount is typically 128 megabytes or less, which is more than enough for a graphical desktop.
    – Keltari
    2 days ago










  • what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards. - they're not. GDDR5 is basically DDR3 optimized for bandwidth (at the expense of latency), if it was up to me, GDDR5 would have been named GDDR3.
    – hanshenrik
    yesterday








  • 1




    @hanshenrik your problem there is that GDDR3 already existed. It was based on DDR2.
    – anaximander
    7 hours ago















up vote
48
down vote

favorite
5












I know that a GPU and a CPU are fundamentally different things and why they both suck at doing the other's job. But what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards.



As I understand it, they're both just different types of DRAM, but it seems to me that the differences could be abstracted away by the memory controller baked into CPU and GPU silicon. The current standard for system RAM is DDR4, but video cards were using GDDR4 for years before DDR4 became a thing for desktops. Video cards are now shipping with HBM RAM (GDDR5?), which is faster than DDR4 system memory.



Why aren't we using the same kind of RAM for both? What makes them different?










share|improve this question






















  • I do want to point out that in some cases the system RAM and graphics RAM are exactly the same. Typically found in lower end computers, the BIOS assigns an amount of the system's RAM to the GPU to use as graphics memory. This amount is typically 128 megabytes or less, which is more than enough for a graphical desktop.
    – Keltari
    2 days ago










  • what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards. - they're not. GDDR5 is basically DDR3 optimized for bandwidth (at the expense of latency), if it was up to me, GDDR5 would have been named GDDR3.
    – hanshenrik
    yesterday








  • 1




    @hanshenrik your problem there is that GDDR3 already existed. It was based on DDR2.
    – anaximander
    7 hours ago













up vote
48
down vote

favorite
5









up vote
48
down vote

favorite
5






5





I know that a GPU and a CPU are fundamentally different things and why they both suck at doing the other's job. But what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards.



As I understand it, they're both just different types of DRAM, but it seems to me that the differences could be abstracted away by the memory controller baked into CPU and GPU silicon. The current standard for system RAM is DDR4, but video cards were using GDDR4 for years before DDR4 became a thing for desktops. Video cards are now shipping with HBM RAM (GDDR5?), which is faster than DDR4 system memory.



Why aren't we using the same kind of RAM for both? What makes them different?










share|improve this question













I know that a GPU and a CPU are fundamentally different things and why they both suck at doing the other's job. But what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards.



As I understand it, they're both just different types of DRAM, but it seems to me that the differences could be abstracted away by the memory controller baked into CPU and GPU silicon. The current standard for system RAM is DDR4, but video cards were using GDDR4 for years before DDR4 became a thing for desktops. Video cards are now shipping with HBM RAM (GDDR5?), which is faster than DDR4 system memory.



Why aren't we using the same kind of RAM for both? What makes them different?







memory graphics-card cpu






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share|improve this question











share|improve this question




share|improve this question










asked Nov 16 at 0:50









Wes Sayeed

10.6k32756




10.6k32756












  • I do want to point out that in some cases the system RAM and graphics RAM are exactly the same. Typically found in lower end computers, the BIOS assigns an amount of the system's RAM to the GPU to use as graphics memory. This amount is typically 128 megabytes or less, which is more than enough for a graphical desktop.
    – Keltari
    2 days ago










  • what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards. - they're not. GDDR5 is basically DDR3 optimized for bandwidth (at the expense of latency), if it was up to me, GDDR5 would have been named GDDR3.
    – hanshenrik
    yesterday








  • 1




    @hanshenrik your problem there is that GDDR3 already existed. It was based on DDR2.
    – anaximander
    7 hours ago


















  • I do want to point out that in some cases the system RAM and graphics RAM are exactly the same. Typically found in lower end computers, the BIOS assigns an amount of the system's RAM to the GPU to use as graphics memory. This amount is typically 128 megabytes or less, which is more than enough for a graphical desktop.
    – Keltari
    2 days ago










  • what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards. - they're not. GDDR5 is basically DDR3 optimized for bandwidth (at the expense of latency), if it was up to me, GDDR5 would have been named GDDR3.
    – hanshenrik
    yesterday








  • 1




    @hanshenrik your problem there is that GDDR3 already existed. It was based on DDR2.
    – anaximander
    7 hours ago
















I do want to point out that in some cases the system RAM and graphics RAM are exactly the same. Typically found in lower end computers, the BIOS assigns an amount of the system's RAM to the GPU to use as graphics memory. This amount is typically 128 megabytes or less, which is more than enough for a graphical desktop.
– Keltari
2 days ago




I do want to point out that in some cases the system RAM and graphics RAM are exactly the same. Typically found in lower end computers, the BIOS assigns an amount of the system's RAM to the GPU to use as graphics memory. This amount is typically 128 megabytes or less, which is more than enough for a graphical desktop.
– Keltari
2 days ago












what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards. - they're not. GDDR5 is basically DDR3 optimized for bandwidth (at the expense of latency), if it was up to me, GDDR5 would have been named GDDR3.
– hanshenrik
yesterday






what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards. - they're not. GDDR5 is basically DDR3 optimized for bandwidth (at the expense of latency), if it was up to me, GDDR5 would have been named GDDR3.
– hanshenrik
yesterday






1




1




@hanshenrik your problem there is that GDDR3 already existed. It was based on DDR2.
– anaximander
7 hours ago




@hanshenrik your problem there is that GDDR3 already existed. It was based on DDR2.
– anaximander
7 hours ago










3 Answers
3






active

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up vote
56
down vote














But what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards.




The GDDR specification, while based on the DDR standard, has its own hardware specification. The DDR specification is technically ahead of the GDDR specification, since GDDR is based on the previous DDR specification (most of the time, except when it's based on the previous GDDR specification).



One of the reasons there is a false belief that GDDR is ahead of DDR is that there have been multiple iterations of the GDDR standard that were based on DDR3. This was also the case with GDDR2, being that its specification has design elements from both DDR and DDR2.




However, it is important to note that this GDDR2 memory used on graphics cards is not DDR2 per se, but rather an early midpoint between DDR and DDR2 technologies. Using "DDR2" to refer to GDDR2 is a colloquial misnomer.




Source: DDR2 SDRAM



Likewise, GDDR4 and GDDR5 both took design elements from DDR3. GDDR5 obviously is an improved GDDR design, when compared to GDDR4.




Like its predecessor, GDDR4, GDDR5 is based on DDR3 SDRAM memory, which has double the data lines compared to DDR2 SDRAM. GDDR5 also uses 8-bit wide prefetch buffers similar to GDDR4 and DDR3 SDRAM.




Source: GDDR5 SDRAM




As I understand it, they're both just different types of SDRAM, but it seems to me that the differences could be abstracted away by the memory controller baked into CPU and GPU silicon.




The two standards are actually vastly different. The difference in the number of bits that can be transferred over a data line is one of those differences. The GDDR specification is not compatible with Intel and AMD x86 processors. The GDDR specification is able to transfer more bits, due to it being connected to an entirely different connection, mainly PCI-e (within the specification of the various revisions of this standard).




The current standard for system RAM is DDR4, but video cards were using GDDR4 for years before DDR4 became a thing for desktops.




This is due to the fact that GDDR4 is based off the DDR3 specification, not the DDR2 specification. The DDR3 standard wasn't ratified until 2005. We didn't see products until 2007 due to entirely different market needs. GDDR4 was announced in 2005 and didn't see products until 2007. So you can see that while they have different names, the actual products were released together.




  • GDDR4 SDRAM

  • DDR3 SDRAM



Video cards are now shipping with HBM RAM (GDDR5?), which is faster than DDR4 system memory.




The current GDDR standard(s) are actually GDDR5X and GDDR6. HBM (High Bandwidth Memory) is a Hynix and Samsung DDR manufacturing process.




Why aren't we using the same kind of RAM for both?




The two standards are not compatible with one another.




What makes them different?




What makes them different is their manufacturing process and their specifications. While GDDR is based off the DDR specification, GDDR is not actually ahead of DDR, although there huge performance gaps between the two standards at this point due to the available bandwidth that GDDR has access to.






share|improve this answer























  • The GDDR specification is not compatible with Intel and AMD x86 processors. not 100% true. AMD x86 processors found in PS4, for example, work directly with GDDR. There it used as both RAM and VRAM.
    – Dan M.
    1 hour ago










  • @DanM. - PlayStation 4 has an APU and used UMA
    – Ramhound
    1 hour ago










  • I don't think this does a great job of explaining what the difference is. This spends a lot of words saying "They're different, despite their confusing naming patterns". It doesn't explain how the two standards are different. I also don't think it's accurate to say that GDDR is connected via PCIe; GDDR memories are typically connected to a GPU, through some bus, which is in turn connected to the computer through PCIe.
    – pbfy0
    43 mins ago










  • @pbfy0 - I focused on a single interpretation of the question. I don’t believe it would be productive to go into depth about the literal differences between the two standards
    – Ramhound
    37 mins ago




















up vote
36
down vote













The underlying tech is more or less the same, GPUs just leverage a much wider memory bus.



GPUs are easier to design this way as a single unit where many memory modules can be directly connected to the processing unit through a custom circuit board. This allows for a very wide memory bus, often exceeding 256-bits. HBM takes this further with with a 1024-bit bus.



CPUs rely on a much more generalized architecture of sockets and motherboard specifications, so more than the standard two 64-bit channels is typically reserved to the high-end and server market.



It should also be mentioned that GPU memory is tuned to trade latency performance for high bandwidth - lots of shoveling and not a lot of seeking. This is not the case with CPU memory where low latency is desired for good random access speeds.






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  • 9




    Your last paragraph is, I think, the most important point: they're optimized for different things. Graphics cards need high bandwidth but aren't as concerned with latency, whereas CPUs need the best latency possible and bandwidth is a more secondary concern. There's no fundamental reason a CPU couldn't use GDDR or a GPU use regular DDR (indeed, many integrated graphics do), it's just that performance would be worse.
    – Nate Strickland
    2 days ago






  • 3




    @NateStrickland CPUs do actually use GDDR as their memory on consoles. Specifically, two last generations of consoles use GDDR as a shared memory for both CPU and GPU.
    – creker
    yesterday


















up vote
3
down vote













One special feature of some types of graphics RAM is that they can be accessed by two independent or mostly independent bus systems - which makes using them as either framebuffers (the portion of video ram where the pixels sent to the screen every 1/60th or so second are kept) or texture buffers easier and doable with less access conflicts and overhead....






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    up vote
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    down vote














    But what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards.




    The GDDR specification, while based on the DDR standard, has its own hardware specification. The DDR specification is technically ahead of the GDDR specification, since GDDR is based on the previous DDR specification (most of the time, except when it's based on the previous GDDR specification).



    One of the reasons there is a false belief that GDDR is ahead of DDR is that there have been multiple iterations of the GDDR standard that were based on DDR3. This was also the case with GDDR2, being that its specification has design elements from both DDR and DDR2.




    However, it is important to note that this GDDR2 memory used on graphics cards is not DDR2 per se, but rather an early midpoint between DDR and DDR2 technologies. Using "DDR2" to refer to GDDR2 is a colloquial misnomer.




    Source: DDR2 SDRAM



    Likewise, GDDR4 and GDDR5 both took design elements from DDR3. GDDR5 obviously is an improved GDDR design, when compared to GDDR4.




    Like its predecessor, GDDR4, GDDR5 is based on DDR3 SDRAM memory, which has double the data lines compared to DDR2 SDRAM. GDDR5 also uses 8-bit wide prefetch buffers similar to GDDR4 and DDR3 SDRAM.




    Source: GDDR5 SDRAM




    As I understand it, they're both just different types of SDRAM, but it seems to me that the differences could be abstracted away by the memory controller baked into CPU and GPU silicon.




    The two standards are actually vastly different. The difference in the number of bits that can be transferred over a data line is one of those differences. The GDDR specification is not compatible with Intel and AMD x86 processors. The GDDR specification is able to transfer more bits, due to it being connected to an entirely different connection, mainly PCI-e (within the specification of the various revisions of this standard).




    The current standard for system RAM is DDR4, but video cards were using GDDR4 for years before DDR4 became a thing for desktops.




    This is due to the fact that GDDR4 is based off the DDR3 specification, not the DDR2 specification. The DDR3 standard wasn't ratified until 2005. We didn't see products until 2007 due to entirely different market needs. GDDR4 was announced in 2005 and didn't see products until 2007. So you can see that while they have different names, the actual products were released together.




    • GDDR4 SDRAM

    • DDR3 SDRAM



    Video cards are now shipping with HBM RAM (GDDR5?), which is faster than DDR4 system memory.




    The current GDDR standard(s) are actually GDDR5X and GDDR6. HBM (High Bandwidth Memory) is a Hynix and Samsung DDR manufacturing process.




    Why aren't we using the same kind of RAM for both?




    The two standards are not compatible with one another.




    What makes them different?




    What makes them different is their manufacturing process and their specifications. While GDDR is based off the DDR specification, GDDR is not actually ahead of DDR, although there huge performance gaps between the two standards at this point due to the available bandwidth that GDDR has access to.






    share|improve this answer























    • The GDDR specification is not compatible with Intel and AMD x86 processors. not 100% true. AMD x86 processors found in PS4, for example, work directly with GDDR. There it used as both RAM and VRAM.
      – Dan M.
      1 hour ago










    • @DanM. - PlayStation 4 has an APU and used UMA
      – Ramhound
      1 hour ago










    • I don't think this does a great job of explaining what the difference is. This spends a lot of words saying "They're different, despite their confusing naming patterns". It doesn't explain how the two standards are different. I also don't think it's accurate to say that GDDR is connected via PCIe; GDDR memories are typically connected to a GPU, through some bus, which is in turn connected to the computer through PCIe.
      – pbfy0
      43 mins ago










    • @pbfy0 - I focused on a single interpretation of the question. I don’t believe it would be productive to go into depth about the literal differences between the two standards
      – Ramhound
      37 mins ago

















    up vote
    56
    down vote














    But what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards.




    The GDDR specification, while based on the DDR standard, has its own hardware specification. The DDR specification is technically ahead of the GDDR specification, since GDDR is based on the previous DDR specification (most of the time, except when it's based on the previous GDDR specification).



    One of the reasons there is a false belief that GDDR is ahead of DDR is that there have been multiple iterations of the GDDR standard that were based on DDR3. This was also the case with GDDR2, being that its specification has design elements from both DDR and DDR2.




    However, it is important to note that this GDDR2 memory used on graphics cards is not DDR2 per se, but rather an early midpoint between DDR and DDR2 technologies. Using "DDR2" to refer to GDDR2 is a colloquial misnomer.




    Source: DDR2 SDRAM



    Likewise, GDDR4 and GDDR5 both took design elements from DDR3. GDDR5 obviously is an improved GDDR design, when compared to GDDR4.




    Like its predecessor, GDDR4, GDDR5 is based on DDR3 SDRAM memory, which has double the data lines compared to DDR2 SDRAM. GDDR5 also uses 8-bit wide prefetch buffers similar to GDDR4 and DDR3 SDRAM.




    Source: GDDR5 SDRAM




    As I understand it, they're both just different types of SDRAM, but it seems to me that the differences could be abstracted away by the memory controller baked into CPU and GPU silicon.




    The two standards are actually vastly different. The difference in the number of bits that can be transferred over a data line is one of those differences. The GDDR specification is not compatible with Intel and AMD x86 processors. The GDDR specification is able to transfer more bits, due to it being connected to an entirely different connection, mainly PCI-e (within the specification of the various revisions of this standard).




    The current standard for system RAM is DDR4, but video cards were using GDDR4 for years before DDR4 became a thing for desktops.




    This is due to the fact that GDDR4 is based off the DDR3 specification, not the DDR2 specification. The DDR3 standard wasn't ratified until 2005. We didn't see products until 2007 due to entirely different market needs. GDDR4 was announced in 2005 and didn't see products until 2007. So you can see that while they have different names, the actual products were released together.




    • GDDR4 SDRAM

    • DDR3 SDRAM



    Video cards are now shipping with HBM RAM (GDDR5?), which is faster than DDR4 system memory.




    The current GDDR standard(s) are actually GDDR5X and GDDR6. HBM (High Bandwidth Memory) is a Hynix and Samsung DDR manufacturing process.




    Why aren't we using the same kind of RAM for both?




    The two standards are not compatible with one another.




    What makes them different?




    What makes them different is their manufacturing process and their specifications. While GDDR is based off the DDR specification, GDDR is not actually ahead of DDR, although there huge performance gaps between the two standards at this point due to the available bandwidth that GDDR has access to.






    share|improve this answer























    • The GDDR specification is not compatible with Intel and AMD x86 processors. not 100% true. AMD x86 processors found in PS4, for example, work directly with GDDR. There it used as both RAM and VRAM.
      – Dan M.
      1 hour ago










    • @DanM. - PlayStation 4 has an APU and used UMA
      – Ramhound
      1 hour ago










    • I don't think this does a great job of explaining what the difference is. This spends a lot of words saying "They're different, despite their confusing naming patterns". It doesn't explain how the two standards are different. I also don't think it's accurate to say that GDDR is connected via PCIe; GDDR memories are typically connected to a GPU, through some bus, which is in turn connected to the computer through PCIe.
      – pbfy0
      43 mins ago










    • @pbfy0 - I focused on a single interpretation of the question. I don’t believe it would be productive to go into depth about the literal differences between the two standards
      – Ramhound
      37 mins ago















    up vote
    56
    down vote










    up vote
    56
    down vote










    But what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards.




    The GDDR specification, while based on the DDR standard, has its own hardware specification. The DDR specification is technically ahead of the GDDR specification, since GDDR is based on the previous DDR specification (most of the time, except when it's based on the previous GDDR specification).



    One of the reasons there is a false belief that GDDR is ahead of DDR is that there have been multiple iterations of the GDDR standard that were based on DDR3. This was also the case with GDDR2, being that its specification has design elements from both DDR and DDR2.




    However, it is important to note that this GDDR2 memory used on graphics cards is not DDR2 per se, but rather an early midpoint between DDR and DDR2 technologies. Using "DDR2" to refer to GDDR2 is a colloquial misnomer.




    Source: DDR2 SDRAM



    Likewise, GDDR4 and GDDR5 both took design elements from DDR3. GDDR5 obviously is an improved GDDR design, when compared to GDDR4.




    Like its predecessor, GDDR4, GDDR5 is based on DDR3 SDRAM memory, which has double the data lines compared to DDR2 SDRAM. GDDR5 also uses 8-bit wide prefetch buffers similar to GDDR4 and DDR3 SDRAM.




    Source: GDDR5 SDRAM




    As I understand it, they're both just different types of SDRAM, but it seems to me that the differences could be abstracted away by the memory controller baked into CPU and GPU silicon.




    The two standards are actually vastly different. The difference in the number of bits that can be transferred over a data line is one of those differences. The GDDR specification is not compatible with Intel and AMD x86 processors. The GDDR specification is able to transfer more bits, due to it being connected to an entirely different connection, mainly PCI-e (within the specification of the various revisions of this standard).




    The current standard for system RAM is DDR4, but video cards were using GDDR4 for years before DDR4 became a thing for desktops.




    This is due to the fact that GDDR4 is based off the DDR3 specification, not the DDR2 specification. The DDR3 standard wasn't ratified until 2005. We didn't see products until 2007 due to entirely different market needs. GDDR4 was announced in 2005 and didn't see products until 2007. So you can see that while they have different names, the actual products were released together.




    • GDDR4 SDRAM

    • DDR3 SDRAM



    Video cards are now shipping with HBM RAM (GDDR5?), which is faster than DDR4 system memory.




    The current GDDR standard(s) are actually GDDR5X and GDDR6. HBM (High Bandwidth Memory) is a Hynix and Samsung DDR manufacturing process.




    Why aren't we using the same kind of RAM for both?




    The two standards are not compatible with one another.




    What makes them different?




    What makes them different is their manufacturing process and their specifications. While GDDR is based off the DDR specification, GDDR is not actually ahead of DDR, although there huge performance gaps between the two standards at this point due to the available bandwidth that GDDR has access to.






    share|improve this answer















    But what I don't get is why standard system RAM has always been a generation behind the RAM used on video cards.




    The GDDR specification, while based on the DDR standard, has its own hardware specification. The DDR specification is technically ahead of the GDDR specification, since GDDR is based on the previous DDR specification (most of the time, except when it's based on the previous GDDR specification).



    One of the reasons there is a false belief that GDDR is ahead of DDR is that there have been multiple iterations of the GDDR standard that were based on DDR3. This was also the case with GDDR2, being that its specification has design elements from both DDR and DDR2.




    However, it is important to note that this GDDR2 memory used on graphics cards is not DDR2 per se, but rather an early midpoint between DDR and DDR2 technologies. Using "DDR2" to refer to GDDR2 is a colloquial misnomer.




    Source: DDR2 SDRAM



    Likewise, GDDR4 and GDDR5 both took design elements from DDR3. GDDR5 obviously is an improved GDDR design, when compared to GDDR4.




    Like its predecessor, GDDR4, GDDR5 is based on DDR3 SDRAM memory, which has double the data lines compared to DDR2 SDRAM. GDDR5 also uses 8-bit wide prefetch buffers similar to GDDR4 and DDR3 SDRAM.




    Source: GDDR5 SDRAM




    As I understand it, they're both just different types of SDRAM, but it seems to me that the differences could be abstracted away by the memory controller baked into CPU and GPU silicon.




    The two standards are actually vastly different. The difference in the number of bits that can be transferred over a data line is one of those differences. The GDDR specification is not compatible with Intel and AMD x86 processors. The GDDR specification is able to transfer more bits, due to it being connected to an entirely different connection, mainly PCI-e (within the specification of the various revisions of this standard).




    The current standard for system RAM is DDR4, but video cards were using GDDR4 for years before DDR4 became a thing for desktops.




    This is due to the fact that GDDR4 is based off the DDR3 specification, not the DDR2 specification. The DDR3 standard wasn't ratified until 2005. We didn't see products until 2007 due to entirely different market needs. GDDR4 was announced in 2005 and didn't see products until 2007. So you can see that while they have different names, the actual products were released together.




    • GDDR4 SDRAM

    • DDR3 SDRAM



    Video cards are now shipping with HBM RAM (GDDR5?), which is faster than DDR4 system memory.




    The current GDDR standard(s) are actually GDDR5X and GDDR6. HBM (High Bandwidth Memory) is a Hynix and Samsung DDR manufacturing process.




    Why aren't we using the same kind of RAM for both?




    The two standards are not compatible with one another.




    What makes them different?




    What makes them different is their manufacturing process and their specifications. While GDDR is based off the DDR specification, GDDR is not actually ahead of DDR, although there huge performance gaps between the two standards at this point due to the available bandwidth that GDDR has access to.







    share|improve this answer














    share|improve this answer



    share|improve this answer








    edited 2 days ago









    psmears

    45238




    45238










    answered Nov 16 at 1:27









    Ramhound

    19k156082




    19k156082












    • The GDDR specification is not compatible with Intel and AMD x86 processors. not 100% true. AMD x86 processors found in PS4, for example, work directly with GDDR. There it used as both RAM and VRAM.
      – Dan M.
      1 hour ago










    • @DanM. - PlayStation 4 has an APU and used UMA
      – Ramhound
      1 hour ago










    • I don't think this does a great job of explaining what the difference is. This spends a lot of words saying "They're different, despite their confusing naming patterns". It doesn't explain how the two standards are different. I also don't think it's accurate to say that GDDR is connected via PCIe; GDDR memories are typically connected to a GPU, through some bus, which is in turn connected to the computer through PCIe.
      – pbfy0
      43 mins ago










    • @pbfy0 - I focused on a single interpretation of the question. I don’t believe it would be productive to go into depth about the literal differences between the two standards
      – Ramhound
      37 mins ago




















    • The GDDR specification is not compatible with Intel and AMD x86 processors. not 100% true. AMD x86 processors found in PS4, for example, work directly with GDDR. There it used as both RAM and VRAM.
      – Dan M.
      1 hour ago










    • @DanM. - PlayStation 4 has an APU and used UMA
      – Ramhound
      1 hour ago










    • I don't think this does a great job of explaining what the difference is. This spends a lot of words saying "They're different, despite their confusing naming patterns". It doesn't explain how the two standards are different. I also don't think it's accurate to say that GDDR is connected via PCIe; GDDR memories are typically connected to a GPU, through some bus, which is in turn connected to the computer through PCIe.
      – pbfy0
      43 mins ago










    • @pbfy0 - I focused on a single interpretation of the question. I don’t believe it would be productive to go into depth about the literal differences between the two standards
      – Ramhound
      37 mins ago


















    The GDDR specification is not compatible with Intel and AMD x86 processors. not 100% true. AMD x86 processors found in PS4, for example, work directly with GDDR. There it used as both RAM and VRAM.
    – Dan M.
    1 hour ago




    The GDDR specification is not compatible with Intel and AMD x86 processors. not 100% true. AMD x86 processors found in PS4, for example, work directly with GDDR. There it used as both RAM and VRAM.
    – Dan M.
    1 hour ago












    @DanM. - PlayStation 4 has an APU and used UMA
    – Ramhound
    1 hour ago




    @DanM. - PlayStation 4 has an APU and used UMA
    – Ramhound
    1 hour ago












    I don't think this does a great job of explaining what the difference is. This spends a lot of words saying "They're different, despite their confusing naming patterns". It doesn't explain how the two standards are different. I also don't think it's accurate to say that GDDR is connected via PCIe; GDDR memories are typically connected to a GPU, through some bus, which is in turn connected to the computer through PCIe.
    – pbfy0
    43 mins ago




    I don't think this does a great job of explaining what the difference is. This spends a lot of words saying "They're different, despite their confusing naming patterns". It doesn't explain how the two standards are different. I also don't think it's accurate to say that GDDR is connected via PCIe; GDDR memories are typically connected to a GPU, through some bus, which is in turn connected to the computer through PCIe.
    – pbfy0
    43 mins ago












    @pbfy0 - I focused on a single interpretation of the question. I don’t believe it would be productive to go into depth about the literal differences between the two standards
    – Ramhound
    37 mins ago






    @pbfy0 - I focused on a single interpretation of the question. I don’t believe it would be productive to go into depth about the literal differences between the two standards
    – Ramhound
    37 mins ago














    up vote
    36
    down vote













    The underlying tech is more or less the same, GPUs just leverage a much wider memory bus.



    GPUs are easier to design this way as a single unit where many memory modules can be directly connected to the processing unit through a custom circuit board. This allows for a very wide memory bus, often exceeding 256-bits. HBM takes this further with with a 1024-bit bus.



    CPUs rely on a much more generalized architecture of sockets and motherboard specifications, so more than the standard two 64-bit channels is typically reserved to the high-end and server market.



    It should also be mentioned that GPU memory is tuned to trade latency performance for high bandwidth - lots of shoveling and not a lot of seeking. This is not the case with CPU memory where low latency is desired for good random access speeds.






    share|improve this answer








    New contributor




    Robert is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.














    • 9




      Your last paragraph is, I think, the most important point: they're optimized for different things. Graphics cards need high bandwidth but aren't as concerned with latency, whereas CPUs need the best latency possible and bandwidth is a more secondary concern. There's no fundamental reason a CPU couldn't use GDDR or a GPU use regular DDR (indeed, many integrated graphics do), it's just that performance would be worse.
      – Nate Strickland
      2 days ago






    • 3




      @NateStrickland CPUs do actually use GDDR as their memory on consoles. Specifically, two last generations of consoles use GDDR as a shared memory for both CPU and GPU.
      – creker
      yesterday















    up vote
    36
    down vote













    The underlying tech is more or less the same, GPUs just leverage a much wider memory bus.



    GPUs are easier to design this way as a single unit where many memory modules can be directly connected to the processing unit through a custom circuit board. This allows for a very wide memory bus, often exceeding 256-bits. HBM takes this further with with a 1024-bit bus.



    CPUs rely on a much more generalized architecture of sockets and motherboard specifications, so more than the standard two 64-bit channels is typically reserved to the high-end and server market.



    It should also be mentioned that GPU memory is tuned to trade latency performance for high bandwidth - lots of shoveling and not a lot of seeking. This is not the case with CPU memory where low latency is desired for good random access speeds.






    share|improve this answer








    New contributor




    Robert is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.














    • 9




      Your last paragraph is, I think, the most important point: they're optimized for different things. Graphics cards need high bandwidth but aren't as concerned with latency, whereas CPUs need the best latency possible and bandwidth is a more secondary concern. There's no fundamental reason a CPU couldn't use GDDR or a GPU use regular DDR (indeed, many integrated graphics do), it's just that performance would be worse.
      – Nate Strickland
      2 days ago






    • 3




      @NateStrickland CPUs do actually use GDDR as their memory on consoles. Specifically, two last generations of consoles use GDDR as a shared memory for both CPU and GPU.
      – creker
      yesterday













    up vote
    36
    down vote










    up vote
    36
    down vote









    The underlying tech is more or less the same, GPUs just leverage a much wider memory bus.



    GPUs are easier to design this way as a single unit where many memory modules can be directly connected to the processing unit through a custom circuit board. This allows for a very wide memory bus, often exceeding 256-bits. HBM takes this further with with a 1024-bit bus.



    CPUs rely on a much more generalized architecture of sockets and motherboard specifications, so more than the standard two 64-bit channels is typically reserved to the high-end and server market.



    It should also be mentioned that GPU memory is tuned to trade latency performance for high bandwidth - lots of shoveling and not a lot of seeking. This is not the case with CPU memory where low latency is desired for good random access speeds.






    share|improve this answer








    New contributor




    Robert is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.









    The underlying tech is more or less the same, GPUs just leverage a much wider memory bus.



    GPUs are easier to design this way as a single unit where many memory modules can be directly connected to the processing unit through a custom circuit board. This allows for a very wide memory bus, often exceeding 256-bits. HBM takes this further with with a 1024-bit bus.



    CPUs rely on a much more generalized architecture of sockets and motherboard specifications, so more than the standard two 64-bit channels is typically reserved to the high-end and server market.



    It should also be mentioned that GPU memory is tuned to trade latency performance for high bandwidth - lots of shoveling and not a lot of seeking. This is not the case with CPU memory where low latency is desired for good random access speeds.







    share|improve this answer








    New contributor




    Robert is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.









    share|improve this answer



    share|improve this answer






    New contributor




    Robert is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.









    answered 2 days ago









    Robert

    34113




    34113




    New contributor




    Robert is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.





    New contributor





    Robert is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.






    Robert is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.








    • 9




      Your last paragraph is, I think, the most important point: they're optimized for different things. Graphics cards need high bandwidth but aren't as concerned with latency, whereas CPUs need the best latency possible and bandwidth is a more secondary concern. There's no fundamental reason a CPU couldn't use GDDR or a GPU use regular DDR (indeed, many integrated graphics do), it's just that performance would be worse.
      – Nate Strickland
      2 days ago






    • 3




      @NateStrickland CPUs do actually use GDDR as their memory on consoles. Specifically, two last generations of consoles use GDDR as a shared memory for both CPU and GPU.
      – creker
      yesterday














    • 9




      Your last paragraph is, I think, the most important point: they're optimized for different things. Graphics cards need high bandwidth but aren't as concerned with latency, whereas CPUs need the best latency possible and bandwidth is a more secondary concern. There's no fundamental reason a CPU couldn't use GDDR or a GPU use regular DDR (indeed, many integrated graphics do), it's just that performance would be worse.
      – Nate Strickland
      2 days ago






    • 3




      @NateStrickland CPUs do actually use GDDR as their memory on consoles. Specifically, two last generations of consoles use GDDR as a shared memory for both CPU and GPU.
      – creker
      yesterday








    9




    9




    Your last paragraph is, I think, the most important point: they're optimized for different things. Graphics cards need high bandwidth but aren't as concerned with latency, whereas CPUs need the best latency possible and bandwidth is a more secondary concern. There's no fundamental reason a CPU couldn't use GDDR or a GPU use regular DDR (indeed, many integrated graphics do), it's just that performance would be worse.
    – Nate Strickland
    2 days ago




    Your last paragraph is, I think, the most important point: they're optimized for different things. Graphics cards need high bandwidth but aren't as concerned with latency, whereas CPUs need the best latency possible and bandwidth is a more secondary concern. There's no fundamental reason a CPU couldn't use GDDR or a GPU use regular DDR (indeed, many integrated graphics do), it's just that performance would be worse.
    – Nate Strickland
    2 days ago




    3




    3




    @NateStrickland CPUs do actually use GDDR as their memory on consoles. Specifically, two last generations of consoles use GDDR as a shared memory for both CPU and GPU.
    – creker
    yesterday




    @NateStrickland CPUs do actually use GDDR as their memory on consoles. Specifically, two last generations of consoles use GDDR as a shared memory for both CPU and GPU.
    – creker
    yesterday










    up vote
    3
    down vote













    One special feature of some types of graphics RAM is that they can be accessed by two independent or mostly independent bus systems - which makes using them as either framebuffers (the portion of video ram where the pixels sent to the screen every 1/60th or so second are kept) or texture buffers easier and doable with less access conflicts and overhead....






    share|improve this answer

























      up vote
      3
      down vote













      One special feature of some types of graphics RAM is that they can be accessed by two independent or mostly independent bus systems - which makes using them as either framebuffers (the portion of video ram where the pixels sent to the screen every 1/60th or so second are kept) or texture buffers easier and doable with less access conflicts and overhead....






      share|improve this answer























        up vote
        3
        down vote










        up vote
        3
        down vote









        One special feature of some types of graphics RAM is that they can be accessed by two independent or mostly independent bus systems - which makes using them as either framebuffers (the portion of video ram where the pixels sent to the screen every 1/60th or so second are kept) or texture buffers easier and doable with less access conflicts and overhead....






        share|improve this answer












        One special feature of some types of graphics RAM is that they can be accessed by two independent or mostly independent bus systems - which makes using them as either framebuffers (the portion of video ram where the pixels sent to the screen every 1/60th or so second are kept) or texture buffers easier and doable with less access conflicts and overhead....







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered 2 days ago









        rackandboneman

        67036




        67036






























             

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