Windows 2000 performance problem.

Running a VFP 7.0 client/server application in a 10Mbits Local area network running Windows 2000 Server and Windows/98Se workstations, performance about 1 second.

It same client/server application in a 100Mbits Local area network with Windows 2000 Server and Windows 2000 Professional workstations, performance is very poor ( 7 seconds ).

When a Notebook Pentium II 366Mhz running Windows/98Se and 10Mbits PCMCIA are plugged into the 100Mbits LAN, the performance is ok ( 1 second )

Questions:

1.Is it a Windows 2000 professional configuration, or Windows 2000 server configuration problem ?
2.Could it be a Active diretory configuration problem ?
3.How can I solve this problem ?

Thanks,
Fadul.