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Part Recommendations

mrwang420
Journeyman III

VRAM for AMD APUs part suggestion. For the 10,000th time.

So. I keep having this idea which never seems to catch on but I feel like it would be a great addition.

 

So. One of the major hurdles for integrated graphics on cpu dies like the X3D chips  os that they have to use system memory for their graphics. Which is slower then actual video memory.

 

To fix this problem. Since amd has SAM which allows the cpu to directly talk to gpus. This could be used to create a line of add in cards that have nothing but VRAM for the use of giving integrates graphics a set of cideo specific memory for their use before touching system memory which in theory should greatly increase the speed and efficiency of integrated graphics.     These add in cards featuring just video memory could also potentially be used to give gpus access to extra video memory as well without the need of buying a whole gpu.  This can help with chip shortages as well as letting customers get more life out of their current gpus  and for super low budget gamers can actually make greater use of AMDs APUs like the 7800x3D  caise now its integrated gpu has a bank of memory that is designed for graphics as well as way faster then system memory.  Thus  taking  the integrated gpus abilities from low tier gpu abilities to close to mid tier gpu abilities.   Like some gpus have nothing wrong with them other then lack of video memory. With this people can gain extra video memory without dropping another $500+

 

 

I have been suggesting this for 8 years now.

2 Replies
BigAl01
Volunteer Moderator

I wonder if the memory add-in cards could be faster than system memory?  It might be cheaper and more efficient to use more system memory if the user installed 64 GB of RAM to give a healthy margin to the video card.

 

 


As Albert Einstein said, "I could have done so much more with a Big Al's Computer!".
FunkZ
Grandmaster


@mrwang420 wrote:

One of the major hurdles for integrated graphics on cpu dies like the X3D chips is that they have to use system memory for their graphics. Which is slower then actual video memory. These add in cards featuring just video memory could also potentially be used to give gpus access to extra video memory as well without the need of buying a whole gpu. I have been suggesting this for 8 years now.

It is true that most system memory is slower than dedicated graphics memory. But on a discrete graphics card the GPU and dedicated memory are physically on the same board which allows for very fast transfer speeds. The memory bandwidth of my 7900XT for example is 800GB/s on a 320bit bus.

However your proposed solution to rely on the PCIe bus to transfer data between an add-in graphics memory card and the IGP in the CPU is flawed. The bandwidth of the PCIe bus isn't an improvement over that of system memory, even the latest PCIe 5.0 16x slot tops out at 64GB/s, whereas dual-channel DDR5-6000 memory bandwidth is 96GB/s. Both use a 128bit bus.

Here is a somewhat dated article (2018) comparing the throughput of PCIe 3.0 16x @ 15GB/s to that of DDR4-3200 @ 25GB/s, so the suggestion that this idea was relevant 8 years ago is likewise false.

Even if you overlook the bandwidth limitations of the PCIe bus, I would argue the primary hurdle of IGPs is not memory speed, it is die space. AMD's desktop "G" series APUs give up L3 cache (compared to the "X" series) to gain enough real estate to incorporate the IGP, thus sacrificing performance. And even the top 8700G has a paltry 12CU in comparison to a RX 7600 32CU for example. Dare I mention the RX 7600 has 288GB/s memory bandwidth as well?

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