Check and Set DMA Mode
By: Arie SlobTo view the DMA mode used by your drives, you need to open the Device Manager (Control Panel > System select the Hardware tab and press the Device Manager button) and view the properties of the IDE ATA/ATAPI controllers. Double-click on the IDE ATA/ATAPI controllers entry to expand it, the right-click on the Primary IDE Channel and Secondary IDE Channel entries (one at a time) and select Properties from the menu.
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Now select the Advanced Settings tab. The Current Transfer Mode will be listed. To change, click the selection arrow on the Transfer Mode drop-down box. Remember, DMA is best, but sometimes a CD-ROM won't function properly in DMA mode. So if you find that your CD-ROM uses PIO mode, you can check to see if it will use DMA, but if you experience problems, change it back.
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If you want to know which devices (hard drive or CD-ROM) are connected to a specific channel, on the View tab in Device Manager, select Devices by connection. If needed you can expand the entries by clicking on the + sign in front of the entry.
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You can even see which drive partitions are on which physical hard drive (provided you have partitioned your hard drive) by right-clicking the listing for the drive you want to examine in detail, select Properties and select the Volumes tab and click the Populate button.
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UDMA66
According to Microsoft, UDMA66 mode is disabled by default on a Windows computer with an Intel chipset that supports UDMA66. To enable UDMA66 mode you need to:
- Make sure the device supports UDMA66 mode
- Use a 80-pin IDE cable with the proper pin cut
- Add a registry key
To add the registry key:
- Start the Registry Editor
- Go to HKEY_LOCAL_MACHINE \ System \ CurrentControlSet \ Control \ Class \ {4D36E96A-E325-11CE-BFC1-08002BE10318} \ 0000 \
- Right-click an empty space in the right pane and select New > DWORD Value
- Name the new value EnableUDMA66
- Double-click this new value, and enter 1 as it's Value data
- Close the registry editor
- Restart Windows for the changes to take effect
When you restart your computer, the UDMA66 will be enabled if it is supported by the hardware.