Considering the fact that modules run at cas 4 DDR2 800(400 FSB) at lower than the specified 1.9 volts with no issues, the overclocking potential looked promising. Getting to 900MHz(450FSB) was just a matter of adjusting the voltage to the voltage specified by G.Skill to run the modules at the stock speeds. Looking better! Pushing to 1000MHz (500FSB) required a couple of things from these modules. First was an increase in the vDimm to 1.95 volts and adjusting the CAS latency to 5 was needed to even boot. Still looking good at under 2.0 volts. Now pushing up to 1066MHz (533FSB) was where the drama started for me. I adjusted the timings to 5-5-5-12 to see if the modules would allow a boot at 2.0 volts! No go! 2.1 volts was still a no go, so I had to push 2.2 volts for 1066MHz to become a reality. Pushing higher even with 2.3 volts did not yield any additional increase in memory speed. So with my max speed set at 1066MHz at 2.2 volts, I went for the timings to see if they could be coaxed down any further. 5-5-4-12 at 1066MHz (533FSB) was the best I was able to achieve with the G.Skill Black PI modules.