IDE Controler CMD 0649 PIO Mode 4 only

IDE Controler CMD 0649 PIO Mode 4 only

Post by Rmxhc2 » Mon, 18 Sep 2006 19:27:01


I use the IDE Controller CMD 0649 chipset for my DVDRRW optical rives the
controller is capable of ATA 100. Device Manager shows it as PIO mode 4 &
the Enable DMA box is disabled.
Editing the registry manually I am able to change to DMA mode but it resets
upon a reboot.
 
 
 

IDE Controler CMD 0649 PIO Mode 4 only

Post by MS-M » Tue, 19 Sep 2006 03:48:19

First thing to check is that you have an 80 wire cable and not an old 40
wire.
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IDE Controler CMD 0649 PIO Mode 4 only

Post by Peter » Tue, 19 Sep 2006 08:23:09

PIO 4 is actually multi-word dma 2 which is what many optical drives still
only run at.
 
 
 

IDE Controler CMD 0649 PIO Mode 4 only

Post by Rmxhc2 » Tue, 19 Sep 2006 16:30:02

Firstly I must point out that I have Dual Boot and am running XP Pro on the
same PC for 2 years without any DMA issues
I have six DVDRW drives in the system using 3 IDE controllers all with 80
wire ATA-133cables
4 drives should operate at Ultra DMA Mode 2 & two should operate at Ultra
DMA Mode 4. They operate successfully at these settings when I boot up into
XP Pro.
In PIO mode 4 excessive CPU usage is noticed and the writing speed is
restricted to 4x, this is as expected with PIO mode
Using a Pioneer burner on the M/B IDE channel I can get the correct Ultra
DMA Mode 4, but unfortunately I do not have any spare IDE on my M/B

The issue is with the controller drivers supplied with the OS and not the
hardware set up
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