875 on 0.95? That sounds almost impossible! My 5870 got 925 @ 1.00V, and 725 @ 0.95.
I highly doubt it was at 1.00v. It was likely at 1.063v, which is the next voltage step in many 5870 bios's.
I don't have the card anymore, but CGMiner was setting the V to 0.953, which if I recall bumps the V to the next highest "step", which was 1.000.