the most common questions : Q141591

how NT handles drive translation; Q161563

Concerning DMA and Windows NT:

DMA for IDE drives is disabled by default. If your CD-ROM is DMA capable, you should enable that functionality. This will reduce CPU usage from approximately 75% to less than 10%. First, test the CDROM and IDE disk drives for DMA compatibility. NT enables DMA functionality per IDE channel whereas Win9x enable per device. This is an important distinction to keep in mind. Enabling DMS on a channel with a DMA and a non-DMA capable device can result in NT failing to boot.

There's a utility, dmacheck.exe, on the SP6a CD in the Support\Utils directory on the SP6a CD which can test for DMS compatibiility.

Its the 11th Edition. Need I say more.