Question How much system RAM can the Radeon Graphics R7 iGPU actually make use of?

[ManOfArc]

We have a PC with a Ryzen 5600G and are using the iGPU for our graphics solution right now. I noticed in the motherboard's UEFI that I can set the iGPU to use up to 8GB of system memory. Is the little iGPU actually capable of using that much system RAM, or is there a more practical limit we should be aiming for?

 

[Ralston18]

"Practical limit" - inherently understood. However, the requirement would be to quantify the limit.

My thought would be to set up some controlled testing to discover possible or practical limits.

Baseline the current graphics solution as to the memory resources being used and then methodically work through incremental iGPU increases in the use of system memory/RAM.

E.g., 1 GB, 2 GB, 3 GB, etc.. Or whatever incremental ranges are allowed and appropriate.

Change only one thing at a time.

Then shift to some other viable configuration and again work through the available iGPU increases as before.

You can probably use Task Manager and Resource Monitor to collect data as you go.

May take a bit of trial and error at first - aka the "learning curve". Then go from there.

Should not be too difficult to reach a conclusion.

 

[ManOfArc]

"Practical limit" - inherently understood. However, the requirement would be to quantify the limit.

My thought would be to set up some controlled testing to discover possible or practical limits.

Baseline the current graphics solution as to the memory resources being used and then methodically work through incremental iGPU increases in the use of system memory/RAM.

E.g., 1 GB, 2 GB, 3 GB, etc.. Or whatever incremental ranges are allowed and appropriate.

Change only one thing at a time.

Then shift to some other viable configuration and again work through the available iGPU increases as before.

You can probably use Task Manager and Resource Monitor to collect data as you go.

May take a bit of trial and error at first - aka the "learning curve". Then go from there.

Should not be too difficult to reach a conclusion.

You're right. It would be a tedious process, but nevertheless a good idea. If no one has found any definitive answer for me, I may just do that. Thanks.

 

[LinuxDevice]

I will add that GPUs only use physical RAM, and cannot use virtual memory. A side effect of this is that the iGPU might also require contiguous RAM. This means that if the RAM becomes fragmented, that extra RAM might not be available unless it was reserved during boot (which would cause the RAM to be contiguous on that address block).

 

[palladin9479]

I have the 5700G, inside the bios you can allocate GPU memory but modern OS's have the ability to extend the system memory directly to the GPU. What I did was assign 2GB of memory directly to it in the BIOS, then let the drivers handle the rest. That is an APU, its' not going to be rendering heavy stuff anyway. If you want to see how much system memory your GPU can use then check our dxdiag Display tab.

 

[kerberos_20]

I have the 5700G, inside the bios you can allocate GPU memory but modern OS's have the ability to extend the system memory directly to the GPU. What I did was assign 2GB of memory directly to it in the BIOS, then let the drivers handle the rest. That is an APU, its' not going to be rendering heavy stuff anyway. If you want to see how much system memory your GPU can use then check our dxdiag Display tab.

is it a true extension? or it has to shuffle data from "extended" part into "gpu reserved" part?

 

[ManOfArc]

I will add that GPUs only use physical RAM, and cannot use virtual memory. A side effect of this is that the iGPU might also require contiguous RAM. This means that if the RAM becomes fragmented, that extra RAM might not be available unless it was reserved during boot (which would cause the RAM to be contiguous on that address block).

Now, that's news to me. I had no idea that would be the case. Thank you.
So... would me dedicating all of that 8GB of system memory in EUFI make the RAM contiguous on that address block during boot as you say?

 

[palladin9479]

is it a true extension? or it has to shuffle data from "extended" part into "gpu reserved" part?

Since AGP days graphics cards have had the ability to directly access system memory, it's just slow as the request has to traverse the PCI bus to the CPU. Now since this is an IGP that is already inside the CPU and using system memory, there isn't really any difference. Just run dxdiag and look at "shared memory" category.

 

[ManOfArc]

I dedicated the full 8GB allowed in BIOS (UEFI), booted, and ran DXDIAG. Here is what the re results show under the display tab. Does this tell us anything? I'm a bit of a newbie to all this.

https://imgur.com/wwzHU6v

View: https://imgur.com/wwzHU6v

 

[kerberos_20]

Since AGP days graphics cards have had the ability to directly access system memory, it's just slow as the request has to traverse the PCI bus to the CPU. Now since this is an IGP that is already inside the CPU and using system memory, there isn't really any difference. Just run dxdiag and look at "shared memory" category.

that agp aperture size was a thing from past, nowadays with DMA its unnecesary to have reserved space for freshly decompressed textures reserved in one part of system ram

tbh i havent toyed with igpus since nvidia left mainboards stage (as that was my last igpu nforce4 something)

 

[palladin9479]

I dedicated the full 8GB allowed in BIOS (UEFI), booted, and ran DXDIAG. Here is what the re results show under the display tab. Does this tell us anything? I'm a bit of a newbie to all this.

https://imgur.com/wwzHU6v

View: https://imgur.com/wwzHU6v

I wouldn't do that, you are starving your system for it's own primary memory. I would never set iGPU above 4GB.

 

[palladin9479]

that agp aperture size was a thing from past, nowadays with DMA its unnecesary to have reserved space for freshly decompressed textures reserved in one part of system ram

tbh i havent toyed with igpus since nvidia left mainboards stage (as that was my last igpu nforce4 something)

I didn't say anything about aperture, just that GPU's have been able to directly address system memory since AGP. The original PCI bus could not do this and PCIe has it built in.

 

[Moonstick2]

Although it's gone the other way now, there have been high-end discrete GPUs in the past with huge amounts of VRAM that could never really make full use of it - at the resolutions and levels of detail where that kind of VRAM make a difference, the GPU itself just couldn't push out a playable frame rate. The same will apply to your iGPU.

I'd look at what kind of discrete cards are comparable to your iGPU, see how much VRAM they have and go from there. A quick search suggests it's around a 750 Ti or RX550 equivalent; if so then that would suggest 2 GB, maybe 4 GB at most.

 

[LinuxDevice]

Now, that's news to me. I had no idea that would be the case. Thank you.
So... would me dedicating all of that 8GB of system memory in EUFI make the RAM contiguous on that address block during boot as you say?

Yes, if you could do it. But you cannot do that. Most drivers require physical RAM. If you knew the address block assignment, and could reserve a larger block aligned with those requirements, then you could increase the amount available. I don't know if this is practical on Windows, but some GPU software (e.g., for AI) in Linux sometimes does this (although it is rare to have an iGPU in a desktop...this is why this occurs most often in the embedded controller world). Note that a discrete GPU (dGPU) uses its own RAM, and so nothing reserved from system RAM would help a dGPU (and it is why AI training and execution is willing to pay more for more VRAM on slower dGPUs). This is the realm of iGPU where it helps. A desktop PC with an iGPU does care about this, but I couldn't even begin to tell you on Windows how to reserve a properly aligned address block on boot (on Linux it is a command line to the kernel upon kernel load, which is really easy to do).

 

[Colif]

it can access half your ram. So how much it can access depends on how much you have. It may not use it but its available to it to share.

 

[ManOfArc]

OK, thanks to all for your advice and information. This was more a thought experiment than something I had planned to doing permanently. And yes, a discrete card will be added soon. I was just surprised that the iGPU ran as well as it did.