used 10.4,10.5,10.5a,10.6 all in the last few weeks with eyefinity 5040x1050 (I think) BFBC2 and a few others. No problems.
If I have more then one monitor plugged or O/C in idle core goes to 400.
I use GPU observer from here to keep an eye on it.
blog.orbmu2k.de
Edit: forgot to mention...