This tweak will enable the processor on your Network Card(if your card has one - 3Com,what about the other i'm not sure you have to find out) designed to offload network processing from the CPU.This is disabled by default.

Open the registry find the key [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\
Parameters]
and create and DWORD value if does not already exist DisableTaskOffload.Modify it to 0=use the processor or 1(default)=do not use the processor.

I don't know if this will produce any performance boost but you may try it out.