I recently picked up a new Dual-Core system (P4D running at 2.8 Ghz,
intel 945GTP motherboard, XP Pro 32-bit SP2) but have noticed really
sluggish performance at system boot-time if the system has been shut
off or sleeping a while.

When I first start up, Process Explorer shows DPCs usage go up to 50%
(100% of one core) over the course of a minute, and then it slowly
trickles down over the next 20 minutes or so. If I reboot once things
are running smoothly, it comes up fine, no high CPU utilization. If I
turn the machine off for a few hours or put it to sleep for a while,
and come back, I bump into the problem again.

Latest drivers, latest Microsoft Update files, removing Antivirus
software, all no help. I found a link on Anandtech to
http://support.microsoft.com/default...b;en-us;896256 , which
outlines some issues with SP2 and dual-core systems. I picked up the
patch, it seemed to help a small amount. I checked SpyBot, Adaware, and
HijackThis as well, figuring it might be a virus. It wasn't.

Any suggestions?