Okay, I've just determined the fastest OC I can get at the highest vCore I dare go to, which is a piddly 1.35V. Given that this comp is gonna be on just about 24/7, and I don't intend to replace it for many many years to come, I'm not going to increase the voltage anymore.
Highest OC @ 1.35V: 3.2Ghz.
Will update with new 3DMark06 score, and then overnight Orthos stability check, then GC OC time. Now its 2 mins Orthos friendly, 3.4ghz failed Orthos in as little as 1 sec. RAM at 5-5-5-15, will change to 4-4-4-12 before running benchies.
update: RAM timings changed, Orthos stable 2 mins. Benchmark run at 1280x1024, no AA (same as stock), all tests run.
CPU @ 3.2Ghz score: 5256
I'll let run Orthos overnight, and if its 100% stable till then, I'll call it stable, and start OC the GC.