People may find this article helpful also...
http://www.tascam.com/Products/US-428/W2k_XP_Optimize.pdf
I liked page 11 (I do this manually now) and this one:
XP: Still under Control Panel/System, select the Advanced tab. Click the Performance
settings button and select the Visual Effects tab. Choose “adjust for best performance”
and then select the Advanced tab. Under Processor Settings, select “adjust for best
performance of background services” to ensure lowest latency with ASIO-based drivers
(ASIO drivers run as background services in Windows).
I didn't know this. I'll give it a try.
Also on page 18:
To disable this feature, go to Control Panel, and under “User Accounts” click on “Change
the way users log on and off” and uncheck “fast user switching.”
And page 20:
Windows defaults to continual logging of Input and Output data to your hard drive.
Disabling this will free up some resources. To disable performance logging, go to the
Start menu and select Run. Type in “diskperf –n” (minus the quotes) and hit Okay.
Have fun and let us know if these help.
Steve N.