I'm afraid I can't reproduce the slow startup problem you're seeing. It starts quickly on my Windows XP machine (first start after boot). Although my machine is probably faster than yours (AMD Athlon 64), I wouldn't expect such a difference in the startup time, it takes only few seconds for me to start.
Is it only IceGrid or do other Ice servers also take time to start? You could try to start the node with the following configuration:
icegridnode --Ice.Config=config --Ice.Trace.Network --Ice.Logger.Timestamp
If that's a network configuration problem, this might give us some clues.
Also, I'm unable to reproduce the CPU usage problem. Note that the numbers shown by the GUI are averages of the CPU utilization over the last minute, 5 minutes and 15 minutes so it's expected if it doesn't match the CPU utilization of your machine. However, these numbers should eventually go down if the CPU utilization is low.
Benoit.