I just want to give some people a head's up... maybe this info will help in case you have trouble stabilizing your overclock due to needing high VTT.

I've swamped my corsair 3x2gb dominator 1600mhz cas-8 for some ocz 3x2gb gold 1600mhz cas-8 ram.

After much stress testing, I had been able to lower my 1.475v vtt to 1.435 using the OCZ kit.

Sure, it's not a HUGE difference but this COULD incide that if you're getting errors even with high VTT it might be that the ram is bad (thus I'm waiting for my corsair rma).... somehow the extra bit of voltage can keep things in line, but in reality you'll run into an error eventually due to bad ram.

So, my conclusion is that: bad or error-prone ram = need more vtt to stabilize.