I've deployed SP2 on all my W2k3 servers now so I thought I'd post about a couple of issues I hit in the process in case it helps anyone else out.

1. There was performance problems on a couple of servers that regularly peg their CPU(s). I traced this back to the way the interupt handling was changed in SP2. To fix it I had to use the Interrupt Affinity Tool (intfiltr), which is available in the w2k3 resource kit. You can read about the usage of intfiltr.exe in KB 252867.

2. There was a network connectivity problem with servers using broadcom NICs. This was because SP2 enables Receive Side Scaling (RSS). Basically a driver bug (there's new drivers for some Broadcom NICs on their site). I haven't had the opportunity to schedule some downtime to fix the drivers so I opted to re-disable RSS support instead. You can read how to do this in KB 927695.