With an Intel Pro/1000MT Card in one of the G5’s ;)

2.3->2.3, same conditions.

FTP Push: 34-42mb/sec. 50% Cpu on Recv, 22% Cpu on Sending
FTP Pull: 41-47mb/sec. 30% Cpu on Send, 28% Cpu on Recv

Note: On a pull, the card is much less reliable - it shows up to 50mb/sec, but ends at much lower rates. With the Mac Card, this behavior didn’t happen - it was basically steady the whole way.