ehhh... about doing that...
There's only one batch AMD made to meet demands, the 0409 batch.
It's the only batch in which the cpus themselves are not defective (fully working quads) that AMD, for some reason, decided to disable one core and sell it as such.
People who bought it in late Feb/first week of March are the most likely to get it.
After that, i'm pretty sure all 720s after that do have some sort of defect in them somehow. You may do it, but it's a chance thing, not a definite thing.
The defective core can be totally unstable at all speeds, may make your computer not boot in worst-case scenarios.
best thing to do is get the 955, which just came out.