I'm having a bastard of a time cooling the center card in my 3 x 5870 rig. At stock clocks it's going up to 90C and then throttling back, and eventually crashing out. I've got an 80mm fan cable tied to the cards and pulling air out, got some 120mm 75CFM ones on the way. Any bright ideas? It's in a caseless chassis, in a 16C server room FWIW.
Got an very similar setup with 4x 5870's in one rig and 3 x 5870's in another which are both using test bench cases in a server room at 18C. My temps would hit 89 to 92 degress ( 92 this is when the throttling kicks in from what i have seen) so to remedy this I needed the cold air in the server room to circulate around the cards simple fix was to buy two a cheap desk fans and put them next to the cases pointing directly at the cards blowing air across them. This dropped my temps from 89/92 to 77/74 degrees centigrade thats with the cores at 900 and ram at 900.