My old machine has the title mainboard and a 2600K CPU. You can see the rest of the stats in my sig. I'm having trouble getting the OC to stick, or so it seems.
It will run 4.6GHz all day on pretty low volts, and 4.0-4.2 on stock volts. I've gone into the bios multiple times and set my OC settings, F10 and restart. When it POSTs, it shows 4.6 or whatever else I set it to just fine. It boots into Windows, and when I turn on CPUZ and HWInfo64, both report the stock clock of 3.4GHz. The voltage settings stick, though. About the only thing I haven't done is fully reset the bios.