^ I tried a relatively minor 3.68ghz using my default multiplier, taking your advice, as I was originally overclocking by lower than stock Multi x High FSB (with RAM, NB, HT dropped low to keep them around stock). I have been doing 3.51 with my method just fine, and just 10 mhz higher will result in a crash within 5 minutes of a prime95 test, if not before then - ie, very quickly. I even raised voltages from where I operate now, at 1.456 (vid 1.4+.01 mobo offset, as any lower will not work at that speed) to 1.504.
I turned on prime95, and it usually turns on started, so I went to turn it off, then turn to blend test, and it crashed before I could tell it to stop.
It looks like we must have very different cores. I have to run a higher voltage just to get less than half the same overclock, but I do have an extra core no problemo. I would say our cores are pretty much the same performance - an extra core is usually about .5ghz from what I've seen - but your core may be more optimized for today's games and programs, meaning better SC2 performance than mine
At least I will be able to play SC3 better, ooh! Nice overclock, that's a beast!