I can assure you that you do need to use a UDMA66 spec ribbon cable. I read an article recently that said the same. In Windows 9x go to device manager, double click on the HD Generic IDE Disk. This will load the propeties and the find the tab with a tick box for DMA. You will need to tick this box and reboot. However, be warned, this is not for the faint hearted, and the article warned againest doing this. Just to round up, you will not see any appreciable transfer/speed increase in going UDMA66.