Difference between 40x and 52x CD-r?

Answer 1

The short answer is that 48X and 52X, in terms of media, are really the same thing. The maximum speed of Recordable CDs, according to the Orange Book specifications, is 48X.

The recorder manufacturers are the ones that started marketing their recorders at 52X, this pushed media manufacturers to then market their media as 52X certified.

The reality is you cannot achieve 52X record speeds. The maximum burn speed that we've seen is 47.2X with a full CD. The write speed starts off around 16X to 20X and climbs to about 47X for a full 700Mb CD, and then drops a little during the finalization of the disc.

That's why review sites, like CDFreaks, talk about how long it takes to burn a full disc at 40X or 48X speeds. The combination of the media quality and burn speed influence the overall time to complete the burn. It would be great to have a burner recorder at 48X speed for any size CD because then we could easily figure out the time it will take. Unfortunately, that is not the case, the amount of information on the disc coupled with recorder and media brand contribute to the overall burn time.

And, now, most folks are purchasing combo DVD/CD recorders and these recorders are only certified to burn CDs at 48X or slower. The dedicated CD-R only recorders are going away - everybody is now using these combo DVD/CD recorders so this whole 52X vs. 48X is becoming less important.

Answer 2

The speed that the CD can be read by the drive is the main difference. The 40x drive is slower then a 52x drive. The numbers tell how fast a drive can read information. A 1x drive will read a CD at the minimum speed needed for listening to music. So a 40x reads a CD 40 times faster then required for music. By reading at faster speed this allows for faster data transfer and the drive can read the disk more then once to lessen the chance for data reading errors.