WOW man turn down the memory CLOCK ...Set that memory down to 500 on the mem. Memory speed and bandwith mean nothing! ...Core speed is where its at! ... I run 2 5970(s) at 900core 500Mem 370-375 each core for me. 80-83C
Good luck
I was already running a 5970 WCed before i heard about bitcoin. It's good for 410-420 per core at 1000 and 60c