There have been a few more reports of lag with the TPU server.

I've performed some diagnostics and haven't found anything conclusive, except that the uplink buffer size for my ISP is excessively large. I don't think that's the problem, though.

I did end up making some changes:

[1] Updated the TPU server's NIC drivers.

[2] Disabled the Windows XP firewall on the TPU server.

[3] Ran the Speedguide.net TCP Optimizer on the TPU server, which made a lot of changes.

Let me know if this makes any difference.