Network transfers from XP to 98 are slow??

Quick question:

I have 2 computers networked together through a router, all 100BaseT. One computer is running Windows 98 SE, the other is running Windows XP.

Whenever a file transfer is INITIATED from the XP system, the transfer is extrememly slow. However, if the same type of transfer is initated from the 98 machine, it's over twice as fast. For example, if I'm on the XP machine and send 1GB file to the 98 machine, the network utilization is less than 35%. If I'm on the 98 machine and request the same 1GB file, the network utilization jumps to over 60%. In both instances, the NICs are doing the same thing, the transfer is just originating from a different location.

Why is this? Obviously it's not a hardware problem, but rather some software setting in XP that is slowing the transfer down if initiated from that terminal.

I'd much appreciate any help with this issue, it's extrememly annoying. Whenever I have to transfer large files, I have to go over to the 98 machine just because it's faster there. wtf?!