I used to have a Q6600 (D0) with my P5KPL-CM (same chipset) and I could get it to a stable 20% OC just by using the auto-profile, but to manually overclock it at 3ghz I needed to up the voltage just a little (but well within specified safe parameters) to achieve stability, then after a couple of weeks it just went "poof" on me (the PC just shut down while I was reading a newssite.)
I still don't know what happened, but my warranty got me a new P5KPL-CM and I bought a new PSU just to be sure, from then on I just left it on a 20% OC using the auto-profile, never had a problem since (I kept it for 7 months, I went i7 in July.)
The moral of the story is: although it may have been the PSU that killed my mobo, the P5KPL's just aren't good overclockers.
Still, 3.45ghz is enough for gaming, unless you have 2 4870X2's or something, in which case you probably have the money to buy a better mobo, if you were into professional applications needing a lot of processing power you'd have known you'd be better off with a quadcore, so chill and enjoy your gaming with your 3.45ghz.