Well i was reading up on all the people that were saying 3DMark is a good benchmark for stability, i thought i might as well post the program i use for stabilizing my 3870's overclock with my processor.
"rthdribl" aka Real-Time High Dynamic Range Image-Based Lighting
http://www.daionet.gr.jp/~masa/rthdribl/
run it, set the resolution to the highest you can (windowed) and press "8" on your keyboard (set msaa to 16x) It does not support crossfire (maybe it supports SLi) but it did bring my fps down to 30ish at 1920x1440@8xMSAA
hope it helps
"rthdribl" aka Real-Time High Dynamic Range Image-Based Lighting
http://www.daionet.gr.jp/~masa/rthdribl/
run it, set the resolution to the highest you can (windowed) and press "8" on your keyboard (set msaa to 16x) It does not support crossfire (maybe it supports SLi) but it did bring my fps down to 30ish at 1920x1440@8xMSAA
hope it helps