Direct Memory Access
The advantage of using Direct Memory Access (DMA) with IDE CD-ROM and disk drives is that it lowers CPU usage during I/O transfers. This drastically improves performance when using these devices.
Ensure that your drive supports DMA before making these changes, otherwise it could lead to unpredictable results. To use DMA:
1. Open Control Panel > System > Device Manager.
2. Click the + sign next to the Disk drives entry.
3. Select the drive you want to enable DMA for and click Properties.
4. On the Settings tab, there should be a DMA check box. You can enable this to enable DMS for the drive.
Note: If there is no check box (or it is greyed out), your motherboard chipset does not support the feature. If the check box is not checked after you restart your system, your hard disk probably has been automatically disabled again because the hard disk may not support DMA. If you are unable to restart Windows after the change is applied, boot to Safe Mode and disable DMA from here.