i have a samsung 30 gb uata 66 hd, the ide cable and mother (soyo 6vca) are compatibles with the uata66, but in windows 2000 pro, the hd is in pio mode (i saw this in control panel, system, device manager, primary ide controller, and the dma if available is set).
in win 98 the uata66 works fine.
in win 98 the uata66 works fine.