I'm having USB problems with my KA266-R with Windows 2000. Everything thing was working great (after I figured out that one has to set a zip drive to 'none' in the BIOS for the RAID drives to be recognized by fdisk, etc) until I enabled the USB ports in the BIOS to install an Epson 1270 printer and 1240U scanner. Without even getting a chance to install the drivers (and with the USB devices still turned off, but the port enables), Windows was running noticeably slower. Now it keeps freezing temporarily (5 sec) quite often (every minute or so). When I monitor the CPU usage during the freezes, the usage jumps to 100%. The freezes occur even when I'm not doing anything. Very strange. If I turn off the USB ports in the BIOS, everything is ok again. Perhaps someone can explain this to me (I know that since the USB ports are hot-swappable, the system has to periodically check the ports to see if a device is on or not, but it shouldn't use up this much CPU power).
I've had 2 KA266-R's in the past week and have encountered some very frustrating issues:
On one board, I could not do a warm reboot, even with the newest BIOS. I'd have to so a complete shutdown and power on everytime. Pretty annoying when you're installing Windows, etc. Then the BIOS dissapeared all of a sudden after one of those shutdowns. And there was no BIOS installed when I initially bought the board as well (brand new).
On another board, I had problems getting my hard drives on the RAID channel to be recognized by several different partitioning/formatting applications. After 2 days of constant frustration, someone mentioned that there is a Zip drive issue with the KA266-R. So I set the zip drive to 'none' in the BIOS and everything worke fine.
Many have stated that this board is stable and pretty decent. I don't doubt their claims. Just be forewarned that are some issues with this board, especially in terms of post-production quality control (but this seems to be true of more boards lately).