I built my friend Kevin a system about 4 months ago. The system included 2-HD 7990's in a crossfire config. He doesn't have at the moment money to install a water cooling system in this build. Ths bottom card at full load runs at 74 degrees C but, the top card runs at 91 degrees C at full load. When the top card hits 91 the system goes into a safe mode and shuts down on him. Anyone else running dual 7990's having this problem? At the moment, without water cooling my solution is for him to buy a bigger case that can provide more air flow. The cpu has a AIO Corair 110 on it. I have switched both the cards and I still end up with roughly the same result of the upper card being hotter. Kinda pissed because I just think it's the design of the cooler that is causing this issue.