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GPU-Z not reading dedicated VRAM?



EDIT: Linked to nvidia optimus tech-doc for those who would want it. Page 18 is informative.


First: standard procedure with a problem is to search the forum and then Google it. And for once, the super-solution manual a.k.a. Google was no help last night.:confused:


Context: ran a few test benchmarks beyond the intro with transitioning areas with vanilla settings, some INI tweaks, and a few different nvidia profiles set through Inspector 1.9.7. I was going to upload them in response to Torminater's thread on laptop performance, but I'm glad I checked the format and my numbers before I did because I discovered something interesting.


WT#@!%: My dedicated VRAM shows absolutely no use. Zip. The only active memory while playing Skyrim (or possibly any game, I plan to check later) is dynamic. This makes no sense as my system has dedicated VRAM, and a lot of it for a laptop. On ultra vanilla my FPS rarely drops below 30 except for the occasional stutter loading outdoor plains or forest environments, and interiors and cities run a solid 45-60FPS. The most intense settings and demanding situations I could get into in thirty minutes put me up to 1.7GB at max and Skyrim still ran like glass. I've triple checked my settings to make sure the GPU is the default for tesv.exe and the launcher.



Toshiba Qosmio X870

OS: W8 Pro 64-bit

CPU: Core i7 3610QM @ 2.30GHz base, 3.2 turbo.

RAM: 8GB DDR3 @1600Mhz

GPU: 3GB DDR5 Optimus Nvidia GTX 670M (598Mhz Core, 1500MHz Mem, 1195 Shader) @ 1920x1080

Latest graphics driver: 314.22 WHQL

Skyrim Disk: Hybrid 8GB SSD with 750 GB @7200 RPM


STEP 2.23 up to 1.F Ini Tweaks


Conclusion: From the single whitepaper that hasn't been updated since release on the Nvidia website under Optimus, the only logical answer I can think of is that GPU-Z cannot read the dedicated VRAM behind the integrated chipset, though it is still being used. https://www.nvidia.com/object/optimus_technology.html


If anyone knows any information that could shed some light on this peculiarity or ideas on how to get at and measure my VRAM it would help a ton for my sanity and correctly calculating my benchmarks. I'm wary of actually modding anything in beyond basic fixes at this point because without being able to tell how much active VRAM Skyrim makes use of I expect my performance would nosedive hard and then harder still.

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"how much active VRAM Skyrim makes use of"


Yeah, I don't think anybody can measure that accurately. I could keep adding high resolution textures past the point where the system tells me the whole dedicated VRAM is in use and it still won't stutter. That's because of the VRAM that is being buffered on the go by the card's drivers (at least that's how I understand it) and I can't predict the exact point where I'm going to hit the wall. Then it will start stuttering like mad. But that point is hard to even estimate as VRAM usage will vary depending on your texture choice and other settings, not to mention the cell in the game you measure it in (and how long you've been playing the game for continuously, as the game has trouble flushing the buffer for some reason - hence people using the PCB command on demand in interior cells).


Case in point, take two identical system with the same Skyrim setup, one with a graphics card with lesser dedicated memory, one with larger amount of VRAM and compare the usage. It won't be the same. The graphics card with more VRAM on board will actually show higher use in game, but the gameplay won't suffer on either card. Easy to notice on mainstream systems with something like Radeon 7850 (1GB and 2GB VRAM), where people using similar settings are getting completely different VRAM usage.


My advice would be to just start with a base of 2048+1024 textures and keep replacing the most important textures first and foremost, e.g. upgrade landscapes/dungeons/mountains to 4096 first, then replace models you'll see the most with 2048 textures, then take care of the less important clutter, until you actually run into VRAM issues. 3GB VRAM should be plenty enough on a laptop, you're more likely to run into RAM issues beforehand (the game would crash after certain threshold is reached).

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UPDATE: Partial success. GPU Shark has a tiny little window tucked away in it's settings that can display values for VRAM use on optimus GPUs. Unfortunately there isn't a method to log it or anything that I can tie the monitor into without digging into the code...but at this point I just want to play. So, moving on...


"how much active VRAM Skyrim makes use of"


Yeah, I don't think anybody can measure that accurately.



you're more likely to run into RAM issues beforehand (the game would crash after certain threshold is reached).


Thank you, Besidilo, for restoring some sanity whilst I've been mulling this over.


I figured that I would have plenty of VRAM to run texture mods and the like, but it never hurts to be too careful - without knowing how much Skyrim dumps onto the card vs CPU I guess I'll have to test it the old fashioned way instead of using math. Guess I have a weekend project...


I've seen a lot of discussions about your last statement around the forum (orange) - crashing at a RAM cap between 2.9-3.1GB. Curious to see if laptops compare to desktops in this regard. Might see if ATTK helps out RAM usage if it's the case...after I get my system set. ^^;


Thanks again for your input. Still going to see if I can find a way to log VRAM, but for now I think I'll dig further into STEP and see how it goes. Cheers.

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