RAM Hardware Reserve in AMD Dual Graphics

[kidlatwarfreak]

Good day,

I just need some clarification regarding the RAM hardware reserve when using AMD Dual Graphics. I have a very cheap gaming PC for MOBAs running AMD A10 7860k and Sapphire R7 250 2GB in dual graphics with 8GB 1866MHz RAM (single stick).

I noticed that my RAM Hardware Reserve is at 2GB. Is this normal since i'm using dual graphics? I can't seem to find an explanation about this, even in AMD's website.

 

[Blas]

Yes, that's normal: the discrete GPU you are using has 2 GB of RAM. Your APU's integrated GPU needs to keep the exact same amount of reserved RAM so that both GPU's can access the same data from the two RAM pools. So the APU reserves 2 GB for the iGPU from the system RAM. All normal, nothing to worry about

 

[techgeek]

I think this is the iGPU (on the APU) driver setting aside RAM to use as VRAM. Your dGPU (R7 250) will have it's own dedicated VRAM. I'm betting if you disable the iGPU in the BIOS, this reserved RAM would not show up.

 

[InvalidError]

Disable crossfire: you are running the APU in single-channel memory mode by having only one stick, which will give the IGP a massive performance penalty due to RAM bandwidth being limited to only half what it should be. Crossfire (and SLI) works best when all the (I)GPUs are of similar performance and by handicapping your IGP with single-channel memory, the IGP is most likely dragging down your performance most of the time.

 

[Blas]

InvalidError makes a good point in that you would get better performance if you had two memory sticks, so that RAM could work in dual-channel mode. The integrated GPU will appreciate all the extra bandwidth you can give it.

However your combination of APU and dGPU is a good one, it's quite well balanced. AMD recommends pairing your APU and your GPU: http://www.amd.com/en-us/innovations/software-technologies/technologies-gaming/dual-graphics

If you want to be sure whether it's handicapping your gaming or not, check it: downlaod FRAPS, and check your frames-per-second with and without dual graphics (which you can disable in the BIOS at startup).

 

[kidlatwarfreak]

InvalidError makes a good point in that you would get better performance if you had two memory sticks, so that RAM could work in dual-channel mode. The integrated GPU will appreciate all the extra bandwidth you can give it.

However your combination of APU and dGPU is a good one, it's quite well balanced. AMD recommends pairing your APU and your GPU: http://www.amd.com/en-us/innovations/software-technologies/technologies-gaming/dual-graphics

If you want to be sure whether it's handicapping your gaming or not, check it: downlaod FRAPS, and check your frames-per-second with and without dual graphics (which you can disable in the BIOS at startup).

I think i'm all good now. I tried to disable crossfire and the hardware reserve went down as well. As for FPS-check, im playing DOTA2 and im getting 65-70fps at 1080p with crossfire on. Without it, my FPS drops down to 30 something.

Thanks for the help.

 

[Blas]

So crossfire, even with a single-channel fed APU, was helping, and not just a little, you were basically getting twice as many FPS. Unless you are running out of RAM when in CF mode, i would turn it on again, you seem to be getting most of its benefits. Dual-channel memory would help even more, but even now CF is all sorts of useful