Been running on an 8 core opteron for almost 4 days:
Balance 0.479320 XPM
Unconfirmed: 0.372963 XPM
Disappointing.
Been getting a little more than 1 XPM a day on an i7 @ 2.3 (laptop). I'm running 6 cores most of the day and 8 overnight.
FWIW, I was doing much worse on the original jHPrimeminer, like maybe 0.2 a day or something like that.