Here is the UDMA enabling string for Intel Chipsets in Windows 2000.
If you have any ATA/66 (UDMA/66), or even better, any newer ATA/100 (UDMA/100) EIDE hard disk(s) properly connected (using a good quality 80 conductor IDE DMA66 ribbon cable) to the UltraDMA/66 (or UltraDMA/100) EIDE controller in your computer, it is strongly recommended to enable this setting, to take full advantage of the faster transfer rates these drives are capable of, which are (theoretically) close to 66.66 MB/second (100 MB/second respectively).
You must be logged on as Administrator to be able to do all this.
This option is disabled by default in all Win2000 releases, no matter what (Intel X86 platform) controller/chipset you have.
Note that this setting is NOT activated just by enabling the DMA item from: right-click on your My Computer icon -> click Properties -> Hardware tab -> Device Manager -> IDE ATA/ATAPI controllers item -> select Primary and/or Secondary IDE Channel Properties -> click Advanced Settings tab -> look under Transfer Mode for the "DMA if available" setting (you must also have "Ultra DMA Mode" active under Current Transfer Mode for this to work). Then you need to repeat these steps for ALL your other IDE Devices (drives) found here, numbered this way: Device 0, Device 1, etc. If you only have one IDE Device, select "None" for all others to decrease bootup time. Now reboot when done, so the change(s) can take effect.
To activate the ATA/66 (UDMA/66) setting, you need to run Regedit (or Regedt32) and go to:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Class\{4D36E96A-E325-11CE-BFC1-08002BE10318}\0000
If using Regedt32 uncheck "Read Only Mode" in the Options menu.
Note that the "0000" key above might show as "0001", "0002" or "0003" on your machine, depending on your particular hardware settings. Select the key appropriate to your case.
Right-click to create a new DWORD [REG_DWORD] Value, call it "EnableUDMA66" (no quotes), and type 1 in the Decimal box to enable ATA/66 (UDMA/66) support. To disable it, change the Decimal value to 0, or delete the "EnableUDMA66" Value altogether.
Reboot when done.
THANKS Axel!