Skyrim Crossfire issue known?
Long story short, I have 2 Radeon 6850's running in Crossfire. When they run together, I receive very low performance on Skyrim. With only one card running (I disable Crossfire) and I max everything, including AA and FXAA (x8 and x16 /w the FXAA box checked) and i recieve 50+ fps. Normal?
afaik skyrim doesn't yet support cfx. it was evident in the skyrim performance analysis by tomshardware. check amd's website for latest info.
•Delivers AMD CrossfireX performance scaling for the AMD Radeon HD 5000 Series
•Delivers AMD CrossfireX performance scaling for AMD Radeon HD 6000 Series
•Improves performance 2-7% on single GPU configurations
•Resolve corruption seen when enabling Multi-Sample Anti-Aliasing on the AMD Radeon HD 6970 Series
Apparently the newest driver fixes some problems.
Edit: The new 11.11c drivers can be found here:
AMD has released a follow up 11.11b and 11.11c set of drivers to try to address the issues. Personally I run 5850's in crossfire and am still having problems with the game. Just a very poorly coordinated pc launch. The other platforms have had problems as well, but things are more complex on PC. I've had to use a third party .dll file to resolve the performance issues. I run at 2560x1600 and on Ultra there is a problem that causes the game to slow to a crawl. Alt-tabbing gets it going, but it sometimes lapses back to the super low framerates well below single card performance.
I'd honestly recommend just using 1 card if you're running into a ton of issues-especially if you can run at your target resolution/settings. I hope they resolve this stuff but after a couple of weeks I'm not exactly holding my breath.
Playing Skyrim on a I-5 750 @ 3.8ghz with 8 Gig RAM and using a HIS 4890 I was getting a solid 28-32 fps at high settings. Added a second HIS 4890 and my FPS DROPPED 10+ FPS to 15-17 FPS. I added the AMD profiles and installed Radeon Pro using the settings I found on this guide
I didn't use the Driver Sweeper or CCleaner and I didn't remove my old drivers like the guide suggested. I just added the aforementioned profiles and the Radeon Pro. This UPPED my FPS to a Vsync locked 60 FPS, so I upped my settings to ultra and I'm getting 38-52 FPS depending on where I am in the game; with the lowest FPS in big cities. I can't say exactly why or how this worked, since I added both the profiles and Radeon Pro at the same time, so I don't know if it takes both to work, or just one or the other; but it did work. I'm happy with it.
I'd suggest trying the Anti-Aliasing Mode set to Adaptive(Performance) instead of the lower setting Multi-Setting. It does look much better and only drops FPS a few frames. Setting to the highest setting of Adaptive(Quality) drops FPS drastically, in my case to 28-38 FPS, and in my opinion doesn't look that much better.
Hope this helps. Just FYI the Crossfired 4890s are performing better than or equal to a 6970/5970 ( around $350 ) or a GTX 570 (around $340 ). You can get a pair off Ebay for around $100-$120.