(The following was taken from the Creative Vision Multimedia Kit Review as the same test and explanations are given)

So what does this real-world performance benchmark imply? As you can see, copy times between the 3 CD's vary tremendously. The impact of having a greater number of files is that seek times add to the overall time of the operation. As average seek times on CD-ROM drives are relatively high, the time it takes to search for thousands of files adds up and hence results in a much longer wait than transferring say, a few hundred files. As an example, let us take a 500MB CD filled with one large file (CD-A) and another 400MB CD filled with thousands of files (CD-B).

When trying to copy all the contents of CD-A over to a hard disk (or any other storage media) the initial time to look for the file on the CD may take 85ms. Once the file is found, a steady transfer takes place at the CD-ROM drive's peak rate (depending on current location of the lens). Assuming a read from inner to outer, transfer rates will increase from 22x in the inner area to 52x in the outer edges of the disc (for the sake of argument). What this results in is a relatively quick transfer solely dependent on the burst speed of the CD-ROM drive.

In the case of CD-B, and although smaller in size, will take up considerately more time to transfer due to the fact that each file would take 85ms (again for the sake of understanding) to find and subsequently, initiate transfer of the file. We find this huge difference in the graph especially between CD 1 and CD 3. So in short, the more files you have, the longer it will take to transfer.

Now here is where the difference comes into play. The Asus 50x turned out be faster than the 52x drive although it is rated lower. Why? The answer lies in the overall lower access times of the Asus 50x CD-ROM drive. By reading the above explanation one can conclude that the rating the of a drive isn't the more reliable way of guessing its performance.

In the case of CD-ROM drives, lower access times, coupled with copying a large number of files, results into overall lower copy times as opposed to drives with higher access times.

Conclusions:

As the industry is slowly moving towards greater DVD-ROM support, CD-ROM drives like the Asus 50x drive provides a user with excellent performance which is backed by the Asus name. It turns out that Asus knows what they are doing when manufacturing products other than motherboards. In the Real World benchmarks, the Asus drive performed more like a 52x and in some instances, actually surpassed 52x performance thanks to its relatively low access times.