memtest86 and ocz memtest have nothing to do with graphics at all.. they run from dos and use all of 3 colors. for graphics card testing, use 3dmark 01 03 05, Aquamark, things like that. Those will show artifacts if your overclock is too high. For temperature testing, search for that RTHDRIBL thing, it runs in a window and puts more power through card in 10 minutes than 12 hours of 3d gaming. My video card idles in the 50's, gets into the 70s after hours of gaming.. RTHDRIBL gets my card up to 83-84 in about 1 minute. That's as high s it gets though, so its all good.