This whole review was conducted under the assumption that PowerColor would fix the bad contact between cooler and GPU that was present on my sample (check page 1). Let's hope that the changes by PowerColor will provide similar cooling performance, otherwise large portions of this review will be obsolete.
PowerColor's HD 7990 Devil 13 is the first dual-GPU HD 7990 card that we review. I have to praise PowerColor for making the bold move and engineering their card without any help from AMD. AMD's HD 7990 is still MIA and might never be released at all. The HD 7990 Devil 13 provides awesome performance in games that properly support CrossFire. But many games don't show ideal scaling, or no scaling at all. AMD's CrossFire technology requires profiles for each game to provide maximum performance, which is often a problem with newly released games as AMD is slower than NVIDIA in updating their profiles. Compared to NVIDIA's dual-GPU GeForce GTX 690, the PowerColor Devil 13 is 11% behind in performance when averaged over all our testing.
PowerColor's card also needs a ton of power. The card alone needs up to 550W (in Furmark). During typical gaming, we see power draw in the 260-300 W range, which is similar to what you can expect from two separate HD 7970s in CrossFire. NVIDIA's GTX 690 does better here as well, offering much better performance per Watt.
All this power is converted into heat, which means that the cooler has to work extra hard. PowerColor does use a powerful triple-slot, triple-fan cooler with ten heatpipes total, and it does, after fixing the mounting pressure, a good job keeping the card cool. Temperatures under load are 70°C; PowerColor mentions 80°C from their own testing. Fan noise in idle is pretty high, but load noise is pretty good, given the card's performance class, when compared to AMD's cards. NVIDIA's GTX 690 is much quieter though, despite using a dual-slot cooler.
What really stands out is the epic package that comes with tons of goodies. The included DisplayPort to DVI adapters will make setting up a triple-monitor EyeFinity configuration a breeze. My personal favorite is the included Wiha screwdriver kit. I've bought many of these for all review and computer work. They are indestructible and will get any screw out easily.
Taming the card for overclocking was not easy as you have to disable AMD's Ultra Low Power State (ULPS) for it to work properly. We also had to switch to PowerColor's Turbo BIOS as the normal BIOS would not let us change the clocks of the second GPU. In the end we reached a pretty impressive 1085 MHz GPU clock, which is higher than the original HD 7970 reference design. After manual overclocking the Devil 13 gained almost 17% in performance compared to the normal BIOS. Pretty impressive!
PowerColor is asking $999 for their card, which is the same as NVIDIA's GTX 690. I find it hard to recommend the PowerColor card at that price-point. NVIDIA's card provides the better overall experience, less power, noise, heat, better max OC performance, in a dual slot form factor, and better drivers. On the other hand, PowerColor's card will let you tweak voltages and overclock as much as you want, unlike NVIDIA's latest generation. This will make the Devil 13 very interesting for hardcore overclockers on their quest to break records.

Update: PowerColor just told us that they are working on the mounting issue and halted all shipments of production boards to investigate. No retail cards should be affected.