I have overclocked this Core i7 920 many times, I know what it likes and I know its limitations. Up to this point I have been able to overclock the processor to 4 gigs but there are some benchmarks that it won't handle at that clock, the highest totally stable overclock for this processor has been 3.880gHz with a BCLK of 194 and a ratio of 20.

I spent a considerable amount of time experimenting with various settings, and testing them, and the processor performed as it typically has in the past. At one point after clearing the CMOS, I decided to just raise the BCLK and CPU voltage, and leave everything else on Auto, something I nearly never do anymore.

And whadda ya know, I was able to push the 920 to its highest clock yet, 4.225gHz, using a BCLK of 211 and a ratio of 20. I did have to set the VCore to 1.485v, so I really recommend you have a good cooler before attempting this kind of clock.