Enabling DMA on Optical Drives


I have two LG Optical Drives connected to the second IED Channel of my MB using the supplied No.40 Cable.

The DVDRAM Drive is Master and the CD-RW Drive is Slave. In device manager the DVDRAM Drive shows as DMA Mode but the CD-RW shows as PIO Mode.

I have not been able to enable DMA Mode on this slave CD-RW. Should this be possible and if so how to enforce its enabling? I have tried doing this in device manager but after reboot it always defaults back to PIO.

Any comments or suggestions would be welcome.


Check to see how BIOS detects it.


I’m not sure where this would appear in the BIOS settings and what to look for.

I’m very much a lay person when it comes to matters of BIOS settings etc. As far as I recall there appears to be no specific BIOS information relating to DMA/PIO settings. Most BIOS settings seem to be set to auto detect.

I do know that my System HDD runs in DMA Mode and is connected to IED Channel 1, my second HDD is connected to SATA 1 connection as IED Channel 3 Master, the two optical drives are as stated in my first post and SATA (IED Channel 4) is unused. All but the CD-RW run in DMA Modes.

Could you be more specific as to where I should be looking in the BIOS settings for this information?

Thanks for your response.


Just as a side note it’s IDE not IED.


Thanks for your contribution. Actually, I knew that and don’t know why I put IED. A slapped wrist, perhaps!

It should be in BIOS how it was detetced, or if its on auto, force it to be detetced. It may automatically detect as PIO mode. Windows will take the settings of what was in BIOS and override what you set it to, if the option even appears.

Can you at least post what BIOS your m/b is using, what version, and what m/b you have, maybe someone has one similar or knows where to look and can telly you.


My motherboard was an Abit IC7 version 1.0 with the latest version 2.5 of the BIOS. Unfortunately, as they do, the Northbridge Heat Sink/Fan assembly detached itself from the motherboard due to a connecting loop failure (common, I believe with this and other Abit boards). Being only four months since purchase, the PC is back with the vendor for attention.

I posted this enquiry to make sure that DMA is possible with my setup so that whilst the PC is being sorted, I could insist he put this problem (and others) to rights.

I didn’t want to look a pratt if it is the current set up is normal with my master/slave connection.

Thanks for your reply - I shall now be able to pursue this anomoly with confidence.