Yeah, there is some mad artifacting with 4870 and OC. My XOC artifacts right out of the box. ATITool will show it to you easy. I finally managed to get a stable 850/1150 thought, artifact free and very solid. Max GPU temps are around 65C. The volts are 1.349 core and 1.598 memory.

Btw, if you want the XOC BIOS I posted it here...

http://www.xtremesystems.org/forums/...190990&page=27