View Full Version : lower FPS in CS:S (only) with SLI than without

03-09-06, 07:05 PM
I got SLI setup today and notice significantly higher FPS in 3DMark06 and FEAR. However, using the HL2 / CS:S video stress test I only get 123 FPS when I usually get 149 with one card.

These are the settings i used for both:
-All settings are on high
-Vsync disabled
-4x AA and 8x AF

Any ideas?

03-09-06, 07:09 PM
Extra CPU over head, in order for SLi to work correctly it needs extra CPU cycles. As HL2 engine is getting old it's now the CPU thats the bottleneck.

03-09-06, 07:33 PM
Extra CPU over head, in order for SLi to work correctly it needs extra CPU cycles. As HL2 engine is getting old it's now the CPU thats the bottleneck.

Whatever way you look at it, that can't be right.
All that SLI does is balance the GPU load, it doesn't put anymore burden on the CPU, if anything it reduces it.

Reinstall your drivers, or even try the new betas.... to begin with.
Then take it from there.

03-09-06, 07:34 PM
The profile is messed up for some reason. There are a few different fixes if you search the forum. I found that CS:Source was actually using the HL2 profile so I ended up copying the CS:S SLI value to the HL2 profile and that fixed it for me. Didn't notice a difference with HL2 either. Someone else mentioned another fix today in one of the threads and there in the gaming section somewhere. I'll see if I can find the other fixes and post them here.

03-09-06, 07:35 PM
Thanks for the reply, something else to mention that just came to mind

I noticed through 3dmark that the core clock speeds for the cards are only 414 compared to 450 with a single card. Is it possilbe that CS:S is using only one card at that lower clock speed?

03-09-06, 07:37 PM
Below is the one mentioned by Wolken007 earlier today. I really think it's just a profile problem that you're having. 3DMark is kind of flakey with the clock speeds it reports.

There have been some posts about the CS:Source FPS loss before. A solution that was presented was modify the hl2.exe and cs:source SLI profiles to use AFR2 and you'll see the return to normal frames. Without this modification I only get about 110 FPS in the stress test. Once adjusted, I get 170+. Hope this helps.

03-09-06, 07:40 PM
sorry for my ignorance, but how do i go about doing that? that is how to set it to use "ARF2"?>

03-09-06, 07:44 PM
Here is another:

Well, I think I got it working. Enabled mode 8 in coolbits to give me the different sli modes and then changed the global setting SLI mode to AFR2. CS:S VST settings are 16x12, 4xAA/8xAF, vsync disabled, all opts high. Here are the results:

SLI multi gpu/SLI enabled............105
SLI multi gpu/SLI disabled............114
SLI AFR2/SLI enabled...................155
SLI AFR2/SLI disabled...................114

See here for how to create a custom SLI profile.

You can also use nHancer or you can just edit the c:\windows\system32\nvapps.xml file. If you remove the predefined tags next to the SLI value in CS:Source and Half-Life 2 profiles, you'll be able to change the SLI mode (if you have coolbits installed).

I'd probably just read the how-to guide at sli-zone. Then I'd edit the nvapps.xml file to remove the predefined tags and then just use the method they describe to change the value. Nvidai protects their canned SLI values to keep you from changing them by accident. nHancer allows you to override this or you can edit the xml file to remove the tag and then you can change them using the nvidia control panel.

Here is an example:

<PROFILE Label="Guild Wars">
<APPLICATION Label="gw.exe"/>
<APPLICATION Label="gwdev.exe"/>
<PROPERTY Label="multichip_rendering_mode" Value="0x02400001" Itemtype="predefined"/>

If you edit the nvapps.xml file and remove the Itemtype="predefined" tag after the multichip_rendering_mode item you would then be able to change the SLI mode for Guild Wars using the regular nvidia control panel. Be sure to backup your nvapps.xml file before editing though so you can restore it if you mess something up or later want the predefined value.

03-09-06, 08:32 PM
It worked! w00t! Thanks man, you rock.(nana2)

03-09-06, 08:37 PM
No problem. :) Which solution did you use (just so I'll know what to recommend first next time)? :)

03-09-06, 09:46 PM
the last one you mentioned, editing nvapps.xml to allow me to change rendering method. changed hl2 and cs:s to AFR2.

03-09-06, 10:55 PM
Cool, thanks for the info.