Id never do that. Started at 650MHz for a temp check- Riva wouldnt display the temp at all, and the coldbug had kicked in. Went to 700, 750, 800, 850, 900, 950MHz and 1GHz. Only one or two artifacts in Nature.
Heres the 950MHz run- you can see part of it in the 1GHz rivatuner pic as well.
iv turned the TEC down and will test again tomorrow (day off work) im hoping to avoid the coldbug and the score will be "normal" (and the clocks will be much lower...)