cd rom - dma



after having a few probs and reinstalling OS a few times, playing around..
i was looking through device manager and under the secondary IDE channel option.. it says my primary CD Rom is only using PIO while the CDRW is using multi-word DMA mode 2
i'm sure the primary 50X cdrom used to use that too.. and i'm sure it used to run faster.
any idea why ? or how to fix it?

greatly appreciated.. thanks


check to make sure that that the ide channel is set to use DMA if available and make sure that the settings are correct in bios.

if the problem remains, pull out the IDE cable from ur mobo that the cd drive is on and switch it around to the other slot (ie primary to secondary). this worked for me, since the mobo got it into its head that the drive couldnt use dma, so switching it to another slot made it reinitialise the drive and pick up dma.

btw, each cdrom was on a separate cable, with its own slot, so i didnt have to move around any hdd's


Retired Mod
Political User
First check the BIOS. It should be set to DMA or Autodetect.

Then check Windows. Open the system control panel, then the Device Manager from the hardware tab. Open the properties for the ATA/ATAPI controllers and select either the Primary or Secondary channel (depending which one the drive is on), and go to the advanced tab. Make sure "Use DMA If Possible" is selected from the menu under the correct Master or Slave position.

If its still PIO, then its all your drive supports. My CD-RW only works in PIO 4, where my DVD-ROM is Multi-Word DMA Mode 2



I had a similar problem. In the end, it turns out the BIOS setting for the CD-Rom had it at ULTRA DMA Mode 2, I set the Ultra DMA to disabled for the CD-RW, and the next time Windows started it changed from PIO 4, to DMA 2.


OSNN Senior Addict
Try using search you would have found my early solution m8ty

Open REGEDIT and find the following keys:

entcontrolset\control\class\ {4D36E96A-E325-11CE-BFC1-08002BE10318}\000x

Last four digits are likely 0001, 0002. Under those keys you will find MasterIDdataChecksum, SlaveIddataChecksum. Delete the value corrosponding to your drive by right clicking on the master and slave checksums and then choose modify and delete the value data box contents do this to both 0001 and 0002 lines.

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