I am using a Diamond Monster Sound MX300 under XP RC2 and I am having trouble with it. Every time I try to copy files from one drive to another or if I search for files, all sound stops and the only way to get it back is to restart. I am using the Aureal AU8830 reference drivers built into XP. I also tried the 2k beta drivers from http://www.vortexofsound.com. Those drivers work for XP but they still have the same problem. Here is my hardware:
 
Abit KT7A-RAID (VIA KT133A chipset)
AMD Athlon Tbird 1.2G/266FSB (running at 12x100 since unstable at 133FSB)
256MB Crucial CAS2 PC133 (Running at CAS2 100mhz. May be the cause of my instability? Will try different RAM later.)
Hercules GeForce2 MX (Latest non-MS certified)
Diamond Monster Sound MX300 (tried XP reference drivers and beta)
Highpoint HTP370 (built into motherboard with 1.11 BIOS and drivers)
Linksys LNE100TX v4 (XP drivers)
Adaptec AVA-1505 SCSI (XP drivers)
ACPI disabled
Maxtor ATA66 20GB
Maxtor ATA100 30GB
IBM ATA33 10GB
Toshiba DVD
HP CD-Writer 9100
Iomega ZIP 100 SCSI
 
I didn't have this problem before under Windows 2000 (then again I was using different hardware at the time).