woohoo! my tri-core doubles as a quad-core!
I consciously went with an phenom II 720 be thinking that the disabled core would save power and would alow my system to run a lot cooler and thus quieter, and so far it doesn't disappoint. Recently however I discovered I am one of the lucky ones who can enable the disabled core. I've ran benchmarks which confirm the performance gain and submitted it to about an hour of prime 95 (haven't had time for more) which seem to indicate it runs stable.
The only draw backs so far are that the temperature sensors don't work when the extra core is enabled and my system will sometimes lock up during the boot process right after I altered the bios settings (acc to "auto" on a gigabyte ga-ma790gp-ds4h). Other than that I assume the extra core will reduce the oc potential somewhat (haven't really bothered with oc-ing that much yet).
The best part as far as I'm concerned is that I can enable and disable the extra core whenever I want. So aside from raising the multiplier I have another option to add to the lifespan off my new pc. Best bang for buck pc component I ever purchased!
and here you have it:
update: so far I've had it up to 3.2 GHz on stock voltages, with all four cores activated and have yet to experience any sort of instability. I've found one of the draw backs of an ulocked multiplier is that raising it will cause cool and quiet to stop working. I am able to run power management profiles through an app called PhenomMsrTweaker, but it has been quite a bit of trial and error to get this to run the way I want it to (and I suspect some firefox issues may be the responsibility of this same app but am unsure).
update 2: the firefox issues had nothing to do with the above (it was actually a shockwave flash-using add that cripled firefox). I have since done a bit more agressive oc-ing and seem stable at 3.4 GHz (17x200) cores and a 2400 MHz clocked northbridge. when i tried to enable the fourth core the system almost imediatly bsod's while starting a cinebench run. A slight cpu voltage increase seems to counter this however and the test completed normal this afternoon. Have done about half an hour of prime too but decided to go back to three cores as I can't monitor temps and the only working cpu sensor was increasing to over 40 degrees (not sure where this is placed but it is generally quite a bit cooler as the core sensors). I'm sure i was nowhere near the danger zone though, but my cpu fan was getting loud to keep things well within my comfort zone. will probably leave it here for now as i don't see any use to go further at this time and the benchmarking tool i was using passed it's trial period so i am unable to compare performance with past results.