I currently crossfired two 4890 and at idle they run77*c.I think its a bit too hot.I tried rivatuner but it doesnt work .
SPECS:ASUS M4A78T- E MOBO, AMD Phenom II X3 720, 2x HD 4890 (stock XFX),Coolermaster HAF 932
ati wants you to think its normal but it is on the hot side. update catalyst control center and go to the amd overdrive section. put the fan speed at about 40 to 50 percent(depending how loud you can tolerate it) and see how cool it gets. dont up it too high cuz you could screw up the fan motor, ive done that twice once with my 4870 and then once again with my 4870x2 sapphire was good and replaced them and all i had to do was pay shipping but still i was running them at like 60 or 70