BF3 Very low FPS when switching Xfire on

Weird. Almost certainly a driver problem - what is your GPU usage when those fps drops happen? Does crossfire work properly elsewhere?

Do you have ULPS disabled? If not, I'd recommend disabling it.

I haven't had any problems with 7970 Crossfire in Battlefield 3, so I'd imagine that there is some sort of tweak you can do to make it work.

I have to ask, did you also download the AMD Catalyst Application (CrossfireX) Profiles?

thanks for answering: i tried to install the catalyst application profiles but that didnt help either, nor disabling ULPS in registry.
ill install starcraft 2 to see if i get same issues there

i tested it on Starcraft II and i seem to get the same problem: with crossfire enabled i get about 30 fps and with crossfire off i get 85 on average, with everything maxed out on 1920x1200 60hz

Do both GPUs work individually? Are you seeing decent GPU usage on both cards when gaming?

I'm surprised you saw no difference after installing the latest Application Profiles...

i think 12.6 officially was released today... might want to try it out

I have the same problem. I am using a xfire 7770 but I am using a 970 chipset asrock extreme. As you have asked my board only allows for one card to work at 100% the other works at around 30%. EVERY TIME I turn on xfire with any game it drops to 19-20 FPS. With one card I get 60+. The main game i am playing is BF3 but I have also started playing Planteside 2 and the issues is showing there too. does anyone... I mean anyone have any suggestions?

amd FX4110 136watt 1.256v quad core
Asrock 970 extreme3
American trends bios 1.40
8gigs ddr3 dual channel gskill xmp1600
2 amd MSI 7770 xfired Drivers 12.10 with 12.11 applications
PLEASE help....this is such a disappointment...and please don't answer with ..."you should have bought a better card" or "return the 2 cards and get a good more expensive card". Thats not helpful and quite frankly its pretty rude.
If anyone knows of a setting or another driver set to use so I can access the full potential of the system..please please please let me know.

Have you tested both of the cards by themselves to see if either of them have a defect or something?

Ok so assuming I have run with one card each card and there doesn't seem to be a problem. Could it be a compatibility issue with the chipset running xfire? I did find an article about the compatibility of xfire with certain MOBO's chipsets. one confirmed compatible chipset I found listed was the 990fx and the 990. So having a board with a 970 chipset, and the the system running xfire pcie x16,x4 could this be the reason behind it? Anyone else with a 970 chipset having the same problem? Anyone with a 990 chipset having the stutter lag issue? I don't want to buy a new piece of hardware unless I can prove that as the issue.