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View Full Version : Disabling Dual-core optimizations on nVidia hardware


Chalnoth
01-10-06, 01:47 AM
For those of us with dual-core, sometimes there's still a game or two that has problems with the dual-core optimizations. So, in the 81.98 drivers, nVidia implemented an option to disable dual-core optimizations. Unfortunately, the setting is currently a registry hack, and it's not documented properly in the driver release notes, so I'll list my own instructions here.

First, in the registry editor of your choice, go to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\Video

(edit: wierd, the above line doesn't look right...oh, well, you know what I'm trying to write)

Here should be one or more {CLSID} entries. The release notes file on nVidia's site suggests a way to find the correct one that led me to the wrong one, so here's the way I did it.

Systematically go through each one until you find one with a sub-directory 0000 that contains lots of entries. The first entries should all be entries related to game .exe files (game profiles). In my system, there was only one of these (and I have an SLI system), so I suspect if you have more than one, it is due to an unclean driver uninstall at some point. All other {CLSID} entries only had a couple of configuration settings.

Now to enter the new DWORD values. For OpenGL, the value is:
OGL_ThreadControl (set it to 2)
For D3D:
WTD_ExecModel (set it to 0)

You can view the 21st page of the 81.98 release notes for the official instructions.

Fackamato
01-10-06, 10:01 AM
Will this raise the performance on single CPUs?

SH64
01-10-06, 10:20 AM
I would like to use it but the problem is that there are other games/apps that already works well with dual-cores or benefit from them & i dont wanna lose that.

Chalnoth
01-10-06, 03:08 PM
Will this raise the performance on single CPUs?
I doubt it, but you're welcome to try.

Chalnoth
01-10-06, 03:44 PM
I would like to use it but the problem is that there are other games/apps that already works well with dual-cores or benefit from them & i dont wanna lose that.
I don't believe this change will have any impact on this. It only changes the behavior of the driver, and as far as I know, there aren't any games that benefit more than a few percent from the multithreaded driver. This shouldn't impact games that are themselves multithreaded. But it would be nice to do some testing. Got any specific game in mind that benefits greatly from multithreading? If I've got it, I can test for a difference.

SH64
01-10-06, 04:08 PM
Got any specific game in mind that benefits greatly from multithreading? If I've got it, I can test for a difference.

Doom3 (not greatly though).
as for apps : 3DMark03/05 & Aquamark3.

jAkUp
01-10-06, 04:21 PM
Yea 3DMark05 was huge. Doom3 gave me about 10FPS more also.

Chalnoth
01-10-06, 05:38 PM
Doom3 (not greatly though).
as for apps : 3DMark03/05 & Aquamark3.
Yeah, the difference in Doom3 is fairly significant. I just tested with and without the optimizations, and got 66 fps without, 74 fps with (nearly 15%...the difference would probably be more if I tested at low res to stress the CPU, of course, but I have no interest in benchmarks that I don't play).

I don't think 3DMark or Aquamark scores have any bearing on this sort of thing.

Anyway, I never said it was a good solution. But it is out there if you are having problems, and it's a hell of a lot better than switching drivers. Hopefully nVidia will add an option to disable these optimizations to the application profiles soon, just in case the problems aren't fixed entirely.

Now I'm going to try out that hotfix to see if that fixes the issue without having to resort to this.

jolle
01-10-06, 06:53 PM
Serious Sam 2, COD2 (via Patch) and Quake4 (via patch) are the only games I can think of right now that are multithreaded.

Chalnoth
01-10-06, 07:01 PM
Serious Sam 2, COD2 (via Patch) and Quake4 (via patch) are the only games I can think of right now that are multithreaded.
I'll try Serious Sam 2, but I don't have either of the other two right now. Now I just need to figure out how to benchmark the game....

jolle
01-10-06, 07:35 PM
SS2 has some Dual Core related bugs so you might want to patch it..
mouse is really erratic in menu and stuff like that..

nekrosoft13
01-11-06, 10:13 AM
Serious Sam 2, COD2 (via Patch) and Quake4 (via patch) are the only games I can think of right now that are multithreaded.


COD2 and Quake 4 drop in FPS after applying the patch. i had to disable multithreading optimizations in driver to get better performance.

SH64
01-11-06, 10:23 AM
Hopefully nVidia will add an option to disable these optimizations to the application profiles soon, just in case the problems aren't fixed entirely.


Thats certainly a good idea .. i hope nVIDIA read this suggestion!

PTK1982
01-14-06, 06:53 AM
Oh yeah this fixed my problem with swkotor2 (100% cpu usage with all dual core aware drivers). I also tried nvidia method but it didn't work so thank you Chalnoth.

My PC:

Windows XP Home Edition SP2
Intel Pentium 4 Dualcore 3Ghz
Asus P5WD2-Premium
XFX GeForce 7800GTX
Creative Audigy 2 ZS
2GB DDR2 533Mhz Memory
4x 120GB Seagate Barracuda 7.200 SATA in Raid0
Lite-on DVDRW SOHW-1673S
Intel Pro/1000PM Network Connection
Logitech MX1000 Mouse
Logitech Ultraflex Keyboard
Viewsonic VX900-2 19" LCD
Viewsonic N3000W 30" LCD

jolle
02-02-06, 10:22 PM
Im trying to benchmark Quake IV using HardwareOCs tool.
thing is that when I disable DC opts in OGL Q4 will crash with SMP on and off, before finishing the test.
It didnt crash running both single core and dual core with SMP on/off on both with NVs DC opts still enabled.
81.98 FW btw, using the setup in my sig, Beta2 Q4 patch.
Anyone got any idea if I can fix it so I can acctually finish the benchmark?

Chalnoth
02-02-06, 11:44 PM
Try the beta drivers at nzone? Don't have Q4 myself so I have no way to replicate the issue.

jolle
02-03-06, 12:50 PM
wierd, it crashed everytime I tried.. then after I posted I attempted it again after a while and then it ran just fine several tries..

Chalnoth
02-03-06, 01:03 PM
wierd, it crashed everytime I tried.. then after I posted I attempted it again after a while and then it ran just fine several tries..
Odd. Makes it much harder to track down and fix too, unfortunately. Anyway, I personally just hope that there won't be any reason to disable the dual-core optimizations soon.

jolle
02-03-06, 05:21 PM
yeah, might just have been something with the benchmark tool.. using HardwareOCs benchmarking tool.
anyhow here are some numbers from quake 4
DC NV opts enabled, DC NV opts disabled and finally running the CPU as Single core:
640x480 = 128 fps
640x480 = 108 fps
640x480 = 108 fps
at 1280x1024 they all end up 85 fps.