Why it’s not running 100mbps

Hello,
This is a weird stuff i should tell. I have a computer which is multiboot win98 and win2000 both the same hardware and connections. I just notice that once i issue a ping our router in win98 i get result of 1ms througput time. But when i use win2000 and issue ping command i get only 10ms throughput time.

Can anybody tell me how to make my win2k run to 1ms.

Reminder both are connected to a 3com switch.

Thanks.

Gerald.