I purchased my EVGA 9800 GTX+ 512MB card about 1 week ago. All I can say is ...WOW. This thing OC's like no other card I've ever owned!!
853 mem (Default 740)
2050 shader (default 1883)
1180 mem (Default 1100)
All with stock air cooling. And it runs cool...never goes above 65degrees w/ full load (1hr playing Crysis). I haven't tried to go any further, but I believe I haven't it the max OC yet. I cannot beleive the headroom these cards have. The 55mm chip sure has made a difference. You can get much faster clock speeds and cooler temps at the same time.