Mistakenly posted this in hardware first, but it belongs here.

Why would my new second Vista PC have double the latency of my main Mac Pro computer? Granted, the latency is typically in the 200ms range, but I get 90ms on average on the Mac. I tried changing my ethernet cord, and I've logged in one account at a time to test it. No matter what, I get double latency on the PC. It doesn't make anything worse to log into 5 accounts on the Vista PC versus logging into only one account. Inevitably all screens have twice the latency of all screens on the Mac when running 5 on one and 5 on the other.

Any ideas?