Turned off Aero, turfed the sidebar and UAC. Much better.
I have an AMD Athlon64 6000+ (3GHz) X2 with 4GB RAM, and 8600GT etc. with Vista Home Premium. When running NOTHING WHATSOEVER except for start-up programs (PCTools ThreatFire, avast! antivirus, Google Talk, Skype, Windows Sidebar, Atomic clock sync, ObjectDock) and on a fresh boot with no-one else logged on, my computer is using *at least* 55% of the CPU power.
I've checked in Task Manager (in admin mode) and System Idle Process is using most of the CPU power. This would be all OK, as you would expect Sys Idle Process to surrender that power when a program asked for it, but it seems not.
When I have WMP11 open (and I'll usually have Firefox open too), the CPU randomly peaks, causing the music to jump. I check in Task Manager - Sys Idle Process is still top, but the Microsoft music decoder (I can't remember the exe name) is on about 10% CPU - not explaining the 45% hike!
I am temporarily using RealPlayer, but I do prefer the interface and OS integration of WMP, and it has all my playlists! I have tried suspending ThreatFire and closing Object Dock with no result.
Is there anything else I can do?