|in XP/Vista there is no way.|
Back in the 95/98 days you could lower the MTU limit to modem size, around 500 instead of 1500, and it would help with ping times.
But with XP(maybe 2000 too?) and newer on a LAN, you are pretty much stuck with an MTU value of 1500. Unless I just don't know how to do it.
PowerMac 9600(1 ghz G4)
ATi 9200 PCI