I've got pretty much the same spec s you but using an AMD HD6990 and ive not had any crossfire or infinity issues. (although I did have a crash the other day) What issues are you having?

I didn't have any problems with a 280X in Witcher 3 before. I'll try this anyway to see if there are any problems.

For Witcher 3, I am having major flickering issues with 290x crossfire. The new drivers aren't helping out that much. At 1440p, I don't see much of a difference between AA on and off, so I have it disabled. But apparently crossfire doesn't work with AA on.

WHAT ??? @Coxaz, for single GPU use, this driver works wonders... I am running Win10 tp 10125 with this driver & every single one of my games is running waaaay better on my MSI Twin Frozr III R7870... GTA V runs maxed out above and beyond my 2048mb vram without any issues at all (smooth as hell)... Witcher 3 runs infinitely better & that includes running full Hairworks @ x16 tesselation (CCC profile), also camera rotation (especially when riding) is a lot smoother now (is smoother when rotating camera slowly but still needs to be improved)... Project cars has had approx 5 - 9 fps increase for me, although it was playing quite well for me on the 15.4.1 driver (all WDDM 2.0 drivers for win10 tp are buggy until full GCN 1.0 support is added 🙁 :P )... Dirt "Rally" is working silky for me too & that's maxed out. What a game that is gonna be !!! 😉 ... Ffs!, even Crysis 3 is running on high settings without so much as a stutter or any slowdown in GPU intensive scenes. Now that is great driver performance !!! Dragon Age Inquisition is running maxed out at around 45 - 57 fps without issues... So you see bro, This driver kicks the leaked 15.5 drivers squarely in the nuts !!! & feels no shame in doing so :P I cannot however comment on the performance of these drivers with regard to the multi gpu setups out there... My rig (self built)... Mobo : Gigabyte GA-970a-DS3P... CPU : PileDriver FX6300 @4.5ghz... CPU cooling : Corsair Hydro H80i... Gpu : MSI Twin Frozr III R7870 2gb OC @ core : 1205ghz Mem : 1350ghz... Ram : 16gb DDR3 @1600mhz with Xtreme profile (9,9,9,24 cas)... PSU : Corsair CX750 (Bronze certified 80% efficiency @ 100% load capacity)... So you see, a medium level gaming rig throwing out performance close to the 7900 cards... Not bad for a Crappy driver eh? :P :P