Realtek
(http://www.realtek.com.tw/downloads/dlac97-2.aspx?lineid=5&famid=12&series=8&Software=True)
has just released a new set of x64 drivers for their audio chipstets embedded
in many popular mobos (e.g.: ASUS K8N, A8NSLI) and notebooks.

For those who have confidence in my d/l links, here it is:
ftp://61.56.86.122/pc/ac97/alc650/WDM_A392.exe

Installer is 18 megs big because:
"Windows 98Gold/98se/Me/2000/XP/2003(32/64 bits) for Driver only. For
Windows 98 SE, DirectX(R)8 is required to enable advanced features. (Excution
file)"
My download link is even better than the Realtek one.
They for got to place the dot "." befor the "exe" extension. LOL

And here's the Readme: ftp://61.56.86.122/pc/ac97/alc650/README.pdf

Carlos