My #1 rig has an HD7990. It can be a bit ropey so I only run it at I=11, with this I can still watch HD streams or play games while mining. Despite a 3-fan case, the side is off & I have a 1000 m3/hr 'can fan' (formally used for 'indoor gardening' ) blowing under the GPU. With an ambient of 23 degrees, the GPUs are running 78 & 82 degrees. Average hashrate is 4.639 GH/s, WU is 2005/m.
#2 has an HD5870. As this rig is only used for mining, monitoring the pools 7 running a couple of wallets it's at I=14. The side is off that too but it doesn't need extra cooling as it's stable at 67 degrees. Average hashrate is 2.355GH/s, WU=509.9/m.
7990! Beefy! Yeah, these newer algos certainly do have that advantage, being able to use your machine. Of course, any mention of heat or cooling is the perfect excuse to show off this big grill. Found an awesome deal on two Thermaltake 2.0's, $22 each because they had the wrong firmware. One for the CPU, one for the 7950, leaving two smaller ones for the two 6950's that I've gotta replace caps on. Temps? I am completely unable to get the 7950 over 60C, even scrypt hashing, overvolting to 1.3, and running it at 1240/1740. It's a very easy hack/retrofit if you ever have the mind to.
http://i633.photobucket.com/albums/uu53/acatphoto/Tech/BadGirl01.jpg
http://i633.photobucket.com/albums/uu53/acatphoto/Tech/BadGirl02.jpg
http://i633.photobucket.com/albums/uu53/acatphoto/Tech/7950-1240-1740-Firestrike.jpg
DUDE!
I don't think 'The Beast' (My Honda VTR1000 SP-1) has radiators that size, and she has 150 HP.
Colour me 'impressed'