Up to 125% overclock - 1800 -> 2240 mhz
I tested the CPU and determined that it's capable of 2690mhz.
I'm being limited by other aspects of the system and trying to find the best balance.
At this point I'm officially satisfied with the system's capabilities, so even if I have to stop at 125% it will have been a worthwhile upgrade. I wanted to get at least 2.2ghz out of it, and I've accomplished that. I haven't fully tested stability, but I did a few quick and dirty checks and everything's fine. I'll run a full 24 hour stress test after I push it some more.
I only had about an hour to mess with it yesterday, so I'm hoping that once I get some time to really whack at it I'll get some even better numbers.