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SLI and Crossfire Support

Posted: Sun Apr 10, 2016 3:08 pm
by Skid
Not a priority, but it would be nice to have, especially for those of us that use stupidly high resolutions, I figured I would mention it now since I read in another thread your talking to NVIDIA about PhysX.

Re: SLI and Crossfire Support

Posted: Sun Apr 10, 2016 3:24 pm
by Chris_CE
UE4 doesn't support SLI :/

But there might be some light at the end of the tunnel according to this thread: https://answers.unrealengine.com/questi ... t-sli.html

Re: SLI and Crossfire Support

Posted: Sun Apr 10, 2016 3:34 pm
by Skid
That interesting, I guess Dreadnought must be doing something special then, because it has an SLI profile that is using AFR2, and official profile. Well no worries, as I said, not a priority by any means :)

Re: SLI and Crossfire Support

Posted: Thu Apr 28, 2016 6:55 pm
by Chris_CE
Yeah you can code in support, it just takes time

Re: SLI and Crossfire Support

Posted: Sat Jul 21, 2018 4:13 pm
by rutra80
BUMP!
I've put 2nd Radeon R7 260X into my rig and tried to force Crossfire in GRIP - it works, but in "AFR friendly" mode there's flickering, which disappears in more intelligent 1x1 and "AFR compatible" modes, but then in turn there's terrible microstutter even with Frame Pacing enabled in the driver.
So, as it's more or less working I guess it wouldn't take very much effort to make it more compatible? Could you please dedicate some time to make it work better?

Re: SLI and Crossfire Support

Posted: Thu Sep 20, 2018 6:09 pm
by rutra80
Actually Crossfire works perfectly in AFR compatible and 1x1 modes with following settings:
  • Turn off TXAA
  • Turn off PostProcessing
  • Tone down Special Effects
  • Tone down Shadows Quality
First three are obvious as they use previous frames to anti-alias, blur, etc. so they need a lot of transfers between cards as they render alternate frames. No idea why shadows affect Crossfire though. Anyway, with above settings one can get high and smooth framerates in Crossfire configurations.

I also noticed that VSR doesn't work - selecting resolution higher than native doesn't switch screenmode at all.

Why do I bother though, devs don't seem to read these forums anymore...

Re: SLI and Crossfire Support

Posted: Fri Oct 05, 2018 11:06 am
by Queadah
They do mate. They do.
They are mostly active on discord these days though