D925XCV: High Enet activity bogs down system

Hi,

I've noticed in numerous situations where I'm conducting a lot of
network activity (P2P, copying files to/from shared drives, running
rsync between LAN computers) that my system becomes extreemly sluggish.
Even non-network and non-disk intensive tasks like playing back MP3s or
transcoding video are effected severely.

Has anyone seen this before? Is this a known problem? Any ideas what I
can change in my configuration to help this situation?

The board is a D925XCV. The chip is a P4 3.4 GHz. Hyperthreading is
enabled. 1 GB RAM. WinXP Pro SP2.

Thanks!
John