Crossfire working?

[richi902]

can someone tell me if crossfire is actually working on any of the steam games currently available? as far as i know on seriuos sam 3 it is not working and therefore not really playable on a single hd-7750(~20fps), on windows i had ~40fps with crossfire.

[RussianNeuroMancer]

Try to enable CF for SS3 binary using /etc/ati/atiogl.xml config. Probably you need to add something like that:

<profile exename="Sam3">
		<CrossFireCaps>0x00000100</CrossFireCaps>
</profile>

[richi902]

i tried it, but it causes the game to run horrible slower, at ~9fps.
but thanks anyway, i dont know if corteam also needs to add crossfire support to it.

[RussianNeuroMancer]

Report CrossFire issue here http://devgurus.amd.com/community/steam-linux then.

[richi902]

ok, i posted it there, thanks!

[Kano]

I tested Crossfire with SS3 back in december. Usually Crossfire does not change anything but in that case it seems to have got a Direct3D profile (which improves speed by less than 5%) and when you switch the game to OpenGL (thats possible on Win as well) then the speed drops to 36% of single gpu (from 34 fps to 12.4 at start of level 6). The curious thing is that you see the same effect when you use OpenGL on Linux. Tested cards(s): HD 5670 with i7-3770S (stock speed).

Yesterday i did some tests with my Nv GTX 295 as well. I tested the diff between 304 and 313 drivers, cpufreq set to performance or dynamic. I just used the start of the 2nd level of the DLC to compare. Only 304 driver reacted to performance setting going from 14 to 20 fps (high setting for gpu). 313 driver without Multigpu, SFR or AA setting: 36 fps. But with Multigpu set to any other value like On, Auto, AFR the speed dropped to 30 fps. So not even Nvidia manages to gain speed with 2 GPUs but usually loses speed.

So what's the result: best do NOT use CF or SLI on Linux. If you use it on Win be sure you use the default renderer of the game - otherwise artefacts or speed losses are often the case (Verified using Unigine Heaven 3.0 as well, only SLI had some impact on OpenGL speed btw.). In the case you want more speed sell your current card and get a faster one and do not try to use 2 cards of the same kind. If your favorite game is not Killing Floor as this game has got an Nvidia only bug I would prefer Nvidia.