weird CD Speed test results for my Compaq OEM CD-ROM and...

[UALOneKPlus]

I used CD Speed for the first time tonight on my Compaq OEM CD-ROM and LiteON CDRW.

I first used Nero Drive Speed to determine the max speeds for the CD-ROM and CDRW. Drive Speed reported that the CD-ROM speed was only 20X, and the CDRW was 48x, etc...

I used a store purchased music CD with 47 minutes of audio.

During the CD Speed test, my CD-ROM read speed remained at a 8X read, and the CD-ROM Spin rate adjusted downward to keep the read speed at that speed. I double checked with Drive Speed to ensure I hadn't tampered with the settings, and it was okay.

During the CD SPeed test of my CDRW, the CDRW read speed started around 16x, and then adjusted upwards to a final speed of 37x, and the CD spin rate also adjusted upwards as expected. Overall average speed was 29x.

What gives? Why does the CD-ROM stay at 8x? And why doesn't the CD-RW hit 48x?

[vbl117]

DAE speed and DATA transfer speed are different things .
In CD-ROM and CD-RW , DATA and audio transfer speed are not the same .
Most of last generaration CD-ROM drive can only perform DAE ( Digital Audio Extraction ) at 8X CLV ( constant speed ) . Most CDRW but especially Lite-On CDRW performs better in DAE . So your Lite-On CDRW can perform DAE up to 48X Max .

It ll be a pain if you want to burn on the fly because , on my older computer , with my CD-ROM drive ( 4X DAE ) and my CDRW ( 4X burn ) i can only burn audio cd on the fly at 2X speed ( nero explain that for continuous burn i have to use my CD-ROM at half speed , when i try to burn at 4X on the fly it fails because of small interruptions in data incoming ) .


Often DATA CDRW transfert speed is smaller than DATA CD-R transfert speed . It's harder for laser lenses to read data on a CDRW , also there can be electronic components limitations ( limited CDRW chipset reading abilities for example ) . Perhaps media brand is also involved .

[cfitz]

Vbl117 is right. Many drives in general are slower at reading audio discs (DAE) than reading data discs. And your CD-ROM appears to be an older one that can only do it slowly. You should check, however, that you have DMA enabled on the drive properly:

http://www.cdrlabs.com/phpBB/viewtopic.php?t=7625

And then you might also want to read the CD Speed FAQs, particularly about the different reading methods CD drives use:

http://www.cdspeed2000.com/go.php3?link ... al.html#q2

cfitz