Losing 1/8th of total usable VRAM with CUDA and 353.62 W10

[Dufus]

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.

 

[ShintaiDK]

What exactly was tested?

 

[Stuka87]

I doubt it has anything to do with DX12, it sounds like something with nVidia's driver.

DX12 is only active if it is called, and using the tools above, it would not have been used at all. CUDA and OpenGL are quite obviously not DX12.

PS: Where is the source? You are required to post that.

 

[therealnickdanger]

So in one scenario not related to DX12, the latest NVIDIA driver is consuming unknown amounts of VRAM for an unknown reason, resulting in unknown impacts?

*grabs pitchfork*

 

[Creig]

Isn't the 980M based on the 970 which has a 3.5GB + 0.5GB memory configuration? 1/8 of 4GB is 0.5GB. Maybe there's a connection.

 

[KingFatty]

Op: where did you obtain the data that you are presenting as hearsay?

 

[Enigmoid]

Isn't the 980M based on the 970 which has a 3.5GB + 0.5GB memory configuration? 1/8 of 4GB is 0.5GB. Maybe there's a connection.

The 980M has cut shaders but the memory and ROP/L2 interface is in one segment.

http://www.anandtech.com/show/8935/...cting-the-specs-exploring-memory-allocation/2

 

[Kenmitch]

The almighty NVIDIA drivers currently don't get along with Win 10 too good....At least on my rig running a 970.

100% clean install but to be fair it's too early to point fingers.

Still gotta load some games for further testing.

 

[n0x1ous]

The almighty NVIDIA drivers currently don't get along with Win 10 too good....At least on my rig running a 970.

100% clean install but to be fair it's too early to point fingers.

Still gotta load some games for further testing.

Make sure Windows update wasn't mucking around with your drivers. i've not had an issue with 353.62 on a clean windows 10 install

 

[Stuka87]

The almighty NVIDIA drivers currently don't get along with Win 10 too good....At least on my rig running a 970.

100% clean install but to be fair it's too early to point fingers.

Still gotta load some games for further testing.

I have had a hell of a time with nVidia drivers on my laptop with W10, but it is an older GPU (Quadro 1000M). But they do not work correctly.

 

[Sabrewings]

The almighty NVIDIA drivers currently don't get along with Win 10 too good....At least on my rig running a 970.

100% clean install but to be fair it's too early to point fingers.

Still gotta load some games for further testing.

No issues here.

 

[soccerballtux]

Nvidia will not provide comment on DX12Gate/RAMgate!!!! lol...

 

[Kenmitch]

Make sure Windows update wasn't mucking around with your drivers. i've not had an issue with 353.62 on a clean windows 10 install

Took care of that part already.

Issue is with clocks getting stuck in 3d mode. No utilities loaded yet. Using latest gpuz only as stand alone.

Using IE as I don't like edge. Clocks would go into 3d mode and get stuck. Switched to software only rendering. Hit and miss on clocks. Edge browser same effect.

Too early to blame anybody.

Don't use rig much lately so early stage of tinkering around so far. Off tomorrow so I'll see if can track down the issue.

Most users don't monitor clocks of card. Plug and play/pray is the norm.

 

[Dufus]

Isn't the 980M based on the 970 which has a 3.5GB + 0.5GB memory configuration? 1/8 of 4GB is 0.5GB. Maybe there's a connection.

Just co-incidence and not related. Same problem seen on an older 2GB card.

I doubt it has anything to do with DX12, it sounds like something with nVidia's driver.

DX12 is only active if it is called, and using the tools above, it would not have been used at all. CUDA and OpenGL are quite obviously not DX12.

PS: Where is the source? You are required to post that.

Added to first post. Might be reserving VRAM or just be a bug, thats the question. FWIW the W10 was a fresh install and no internet connection so only manual updates.

 

[ShintaiDK]

Process Hacker doesnt work correctly in Windows 10. Hell it doesnt even work correctly in Windows 7.

Process Explorer vs Process Hacker in Windows 10.

 

[n0x1ous]

Most users don't monitor clocks of card

Agreed and I do the same

 

[Dufus]

Process Hacker doesnt work correctly in Windows 10. Hell it doesnt even work correctly in Windows 7.

No need to use Process Hacker specifically.

Result is the same with Process Explorer.

However 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.

Thread title updated.

Note that with 10.18.13.5362 under W8.1 it works as expected.

 

[ShintaiDK]

Remember Windows 10 is still at best beta. Including tools for it.

Also you compare 2 different systems and OSes.

My observation is that Windows 10 uses more VRAM for GUI tasks and this is hidden from the tools. I usually use 500MB+. While on Windows 7 it was 300MB+. On Windows 8.1 this is much lower.

 

[soccerballtux]

pay the NVidia tax! time to upgrade!

seriously though.

it'll probably be taken care of though.