yes I do oc, but only my C566@850, but thats not the matter, yesterday I took off my 8500 and put in a GF2MX400 from my other system - now it works, vice versa I put in the 8500 in the other one, which is a T1.4/Abit KT7-A which now works, too. So I guess it's the AGP4x which the BX6-2 is not...