I recently bought a refurb XFX Geforce4 Ti4200. I tested it overnight at 290/590 and all seems to be well. I bumped it up to 300/600 and still no hiccups. I am currently trying 300/610. I am testing with 3DMark2001SE, Dronezmark, and Evolva Rolling Demo. How do I know when it's OC too high? Jaggies, lockups, or what?? I remember with my old TNT2 Ultra I would get white spider web like lines when I clocked it too high. TIA.