Your DVD-ROM has slowed down, your DVD-Burner is only burning at lower speeds, your PC has almost locked up whilst reading or burning DVD's and the CPU usage has rocketed whilst reading or writing.

These are all classic symptoms of your drive operating in PIO mode instead of DMA mode.

This problem occurs in Windows XP when the drives have been used to read discs that have errors on them. After about half a dozen of these read errors the drive controller reverts from DMA mode to PIO mode, which is the old and inefficient way of using them.

This is a simple problem to cure: all you need to do is to reset the operating mode to DMA rather than PIO.

Follow These Steps in WindowsXP
1) Right click the My Computer icon on the desktop and click Properties.
2) Select the Hardware page and click the Device Manager button.
3) Locate the Primary and Secondary IDE Channels, and double click on the one your hard-drive is connected to (usually the Primary IDE Channel).
4) Open the Advanced Settings page on the IDE Channel Properties window that appears.
5) Click the Transfer Mode dropdown box and select "DMA if available".
6) Click on the OK button to confirm the changes.
7) That's it, you've just enabled DMA. Depending on the number of devices you have on your system, it could be useful to do this on the Secondary IDE Controller as well, and to both devices on each of them.

Alternatively, if you find your drive is locked in PIO mode it is simply a matter of uninstalling the appropriate controller in Device Manger by right clicking on it and selecting uninstall and then rebooting a couple of times and it will then have been reset to DMA mode. Most DVD drives are UDMA2 or similar with the newer faster drives like the Pioneer 108/109 being UDMA4.
The drives will not work in the faster DMA mode unless you use 80 way UDMA IDE cables, 40 way cables are likely to slow your system down Read this for details on IDE cables

Here is what Microsoft has to say about this problem: microsoft.com and here

Added:  Friday, March 12, 2004
Reviewer:  Flash

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