Do you know what the VID is on your chip? You can find it by using Coretemp. A couple of members on here including myself have had trouble getting stable beyond 2.9 w/out insane amounts of voltage. Since you have 4gb of ram now it will be harder to oc the ram. It also puts more stress on your Northbridge which sometimes can require additional voltage just to run 4 sticks at 800mhz which in turn will hurt your CPU oc. 1066mhz seems to be fine when running 4 sticks but anything after that seems hard to get stable. Just oc like you've been doing.