All of the Opteron UP 1xx chips use the San Diego core.
The San Diego core also is used in the socket 939 A64 3700+, 4000+, some later FX55s & FX57.
The 3700+ runs at 2.2GHz, the 4000+ at 2.4GHz, the FX55 at 2.6GHz and the FX57 at 2.8GHz.
3700+ uses a x11 multiplier, 4000+ uses a x12 multiplier, FX55 used a x13 multiplier & FX57 uses a x14 multiplier.
FX55 & FX57 have fully unlocked multipliers, meaning you can raise them or lower them. 3700+ and 4000+ multipliers are only adjustable downwards, or up to their default x11 & x12 respectively.
With a x9 (upwards locked) multiplier, the Opteron UP 144 is not really equivalent to any of the San Diego A64s, but this doesn't mean it won't clock better! At it default speed, it performance rating is probably 3300.
With the right motherboard (DFI probably the best choice) you could realisticly achieve a 2.7GHz+ clock speed.
Cheers,
Hav