This might be usefull to owners of Radeon HD 4650 AGP graphics cards, using Windows XP.

High CPU usage, even when not running anything in Windows is down to interupts. AGP cannot cope with two devices on the same AGP slot (GFX and HD audio thats built in).

Solution:
Disabling Microsoft UAA Bus Driver for High Definition audio in device manager.

Next problem:
You have to do this everytime windows boot - a hastle.... work around is:

1) download devcon (note: different downloads for 32 and 64 bit) off the microsoft web site.
2) Copy it to the Windows/System32 directory.
3) Open notepad and enter the following line

devcon disable PCI\CC_0403

4) save notepad file as runme.bat and save in your start->Program files->startup folder.

this work around disable the built in HD sound on the AGP graphics card each time windows boots.

Note: PCI\CC_0403 is the Id for the Microsoft UAA Bus Driverfor High Definition audio device, yours may be slightly different - look it up in device manager


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link to the usefull post :
https://forums.tomshardware.com/threads/xfx-radeon-hd-4650-agp-only-pci-mode-windows-7.768196/