CD-ROM UDMA Speeds Question

[ADPankow]

Is their any other standard CD-ROM that has a higher UDMA speed than UDMA/33? I believe some DVD-ROM drives have UDMA/66 but I am wondering if any regular CD-ROM drives do or if UDMA/33 is the standard. Thanks in advance for your replies!

 

[elzt]

I haven't heard of any CD-ROM drives that can go higher than UDMA33. Remember a 1x speed CD-ROM drive gives a data transfer rate of 150KB per second. So a 52x drive will have 7.8MB throughput which is still less than the UDMA33 specification of 33MB/s.

Above 52x speed, there are problems with vibration, noise and heat. So you will not see any faster drives at the moment due to mechanical constraints (Kenwood makes 72x CD-ROM drive though?).

DVD-ROM drives on the other hand, give a transfer rate of 1.35MB/s at 1x speed. That's 9 times faster than a CD drive. So a DVD-ROM drive supporting UDMA33 or above is possible.

 

[GhostKat]

Wouldn't this cause a slow down to any drive that does have a higher UDMA speed and is attached to the same cable?

GK

I'd go inside my computer but it's SCSI in there

 

[lhgpoobaa]

All cd-rom and cd-rw drives i know of are ata33 or less as even when transfering data at max speed the sustained rate is below 10MB/sec, way below the limitaitons of ata33.

most dvd drives also use ata33, allthough the pioneer 16x drives use ata66, even though the max transfer rates of a dvd drive are around 22MB/sec, still well below the ata33 limitation.

as for different speed drives, modern chipsets support independent device timing, allowing different speed devices to work at their own speeds on one cable.
this is also covered in the HDD FAQ.
occasionally problems arise when slaving optical drives to hard drives, but usually this isnt a problem.


<b><font color=blue>I prefer to blend into the background, because it's much easier to sneak up on people and disembowel them that way. Arr!</b></font color=blue>

 

[marneus]

Asus 16xDVD drive runs atDMA100
Several CDRW drives run at DMA66 (never seen DMA100 yet but havent read up on the 48x48x24x drives yet)
CD drives never seen faster than DMA33

besides it is unlikely they will ever actually need the full bandwidth...

no-one shouts louder than someone who is being ignored, or in the case of techies, to be heard over the noise of their PC's ;-)