- Sep 20, 2010
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This was first noticed by a user testing his GTX980M with 4GB VRAM on W10 with driver 10.18.13.5362 and only able to use a maximum of a little less than 3.5GB. It was a strange problem.
Further testing with a GT640 and 2GB VRAM with W10 and driver 10.18.13.5362 showed only 1679MiB free while processhacker showed less than 40MB of dedicated VRAM in use by all processes such as dwm.. Reverting to driver 9.18.13.4411 (DX11.2) same system brought available VRAM back to 1939MiB.
This was also confirmed by requesting all VRAM via CUDA, starting with large blocks and then smaller ones as requests failed until there was no more available VRAM and also by trying to load large textures via OpenGL. With 2GB of VRAM limit was reported as 1.94GB under processhacker.
So does DX12 reserve about 1/8th of the total VRAM which is then no longer usable by the system or is it something else that is causing this?
10.18.13.5362
9.18.13.4411
Original Post
http://forum.notebookreview.com/threads/3-5-gb-0-0-gb-4-gb.779784/
GPUVRam and GPUMem
GPUMem just shows available VRAM
GPUVRam attempts to allocate all VRAM. Note when allocated due to no VRAM left eviction will take place with any other VRAM requests.
Update: After some further testing this limit seems to be CUDA related so either a bug on the CUDA side or the newer driver is purposely limiting CUDA resources under W10.
Further testing with a GT640 and 2GB VRAM with W10 and driver 10.18.13.5362 showed only 1679MiB free while processhacker showed less than 40MB of dedicated VRAM in use by all processes such as dwm.. Reverting to driver 9.18.13.4411 (DX11.2) same system brought available VRAM back to 1939MiB.
This was also confirmed by requesting all VRAM via CUDA, starting with large blocks and then smaller ones as requests failed until there was no more available VRAM and also by trying to load large textures via OpenGL. With 2GB of VRAM limit was reported as 1.94GB under processhacker.
So does DX12 reserve about 1/8th of the total VRAM which is then no longer usable by the system or is it something else that is causing this?
10.18.13.5362
9.18.13.4411
Original Post
http://forum.notebookreview.com/threads/3-5-gb-0-0-gb-4-gb.779784/
GPUVRam and GPUMem
GPUMem just shows available VRAM
GPUVRam attempts to allocate all VRAM. Note when allocated due to no VRAM left eviction will take place with any other VRAM requests.
Update: After some further testing this limit seems to be CUDA related so either a bug on the CUDA side or the newer driver is purposely limiting CUDA resources under W10.
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