My system has been running brilliantly stable ever since I overclocked it last summer.
As you can see in my signature, the CPU has been overclocked at 1333 x 9 (no increase to voltage), but the ram has hardly been touched (still running a standard 800mHz). The only thing that was changed was that I set the timings and voltage (now at 2.1v) to manufacturers recommended settings since they didn't arrive set at them.
I think a memory overclock is on the cards, but I wondering the best way to approach it. Would I have to adjust the CPU settings too? Currently the configuration between ram and cpu is referred to as "unlinked" in bios, probably because the FSB is different. Could this cause any performance issues or bottlenecks?