[Windows NT]NT 4.0 SP2+:Enabling the DMA

Intro

Handling the DMA, for IDE drives is much more difficult under NT4 than under Windows 9x series. Unlike the other versions (Windows 9x, 2000, XP) where activation of the DMA to improve disks speed is quite simple, here no Device Manager Tree utility is provided.

Enabling DMA on Windows NT 4.0 SP2 +:

Check NT service pack

In theory UDMA, can handled by SP2 or SP3. But according to Microsoft, it will work on SP4 or higher.
Conclusion: Better install SP6a to avoid any problem ... If your system is not up to date, you should get an error message when launching the utility.

Download the utility from Microsoft to modify the registry

You manually activate UDMA by modifying the registry. But consider it as a risky procedure, leading to the complete reinstallation of your system.

Fortunately, Microsoft provide a small utility (dmacheck.exe) within the NT4 (with SP4 or higher) CD. Or you download the utility from Microsoft: http://download.microsoft.com/...

Installation

Double-click on the small program to have it unpacked and copied to the root of the hard drive, where your system is installed.

Go in root of your hard drive (C: in most cases).The small program: dmacheck.exe should be now installed

Double-click to run program.

Activate the UDMA for the compatible IDE channel(s),(Channel 0 is the primary IDE controller, Channel 1 the secondary controller)

Once done, click OK, then restart. If the channels where you enabled DMA and disk drives that are attached to them are compatible, everything should runs smoothly.