Crossfire doesn't seem to be working correctly

zinzara

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Jan 18, 2011
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18,510
I have two Sapphire Radeon 280x cards in Crossfire and I'm having some weird issues. I saw some threads around the internet about similar issues but part of my issue doesn't fit. So, I noticed when I have Crossfire enabled in the Radeon Settings app, my secondary card sleeps.

Now for the real-life testing. I started up Witcher 3 (The most intense game I have currently) with Crossfire enabled. Set to Ultra settings. Started it up. When it got to the scene where he's taking a bath (the first in-game CGI) it was lagging horribly. I closed the game, disabled Crossfire, got back to that scene and it plays beautifully with no lag at all. When I do a GPU stress test (FurMark) with Crossfire on, it notes that Crossfire is enabled but the graph only shows one GPU and the list of GPUs only shows one. When I disable Crossfire, the benchmark shows two graphs...I'm really confused. It seems like it's acting the exact opposite of what it should. What is going on?

Other system info if it matters:
AMD FX-8320 (Oct-Core)
16GB RAM
Windows 10 Home 64
*Nothing is overclocked and this is a brand new system I built*

Some additional information. I compared the benchmarks on 1080 preset and got the following:
Crossfire On
SCORE:5233 points (88 FPS, 60000 ms)
Max GPU Temp: 76°C
FPS: min:60, max:100, avg:88 - OPTIONS: DynBkg

Crossfire Off
SCORE:3355 points (56 FPS, 60000 ms)
Max GPU Temp: 77°C
FPS: min:53, max:61, avg:56 - OPTIONS: DynBkg

So it seems like it really is *working* as far as the cards running on Crossfire. But why is the game lagging so much?
 
Solution
D
I don't know much about individual games, but it sounds like the game is not optimised for crossfire, at least with those cards. Are you using normal or force crossfire settings?
D

Deleted member 2121781

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I don't know much about individual games, but it sounds like the game is not optimised for crossfire, at least with those cards. Are you using normal or force crossfire settings?
 
Solution

zinzara

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Jan 18, 2011
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18,510


I had all the defaults set in the Radeon Settings app. I had Crossfire turned to on. That's it. I did a search for "Witcher 3 optimized for Crossfire" and found this: http://support.amd.com/en-us/kb-articles/Pages/Optimizing-The-Witcher-3.aspx

I made the changes and it doesn't lag now.
 
D

Deleted member 2121781

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Oh good, glad the issue is solved.