by Andrey Kuznetcov
03/31/2006 | 12:01 PM
All the loyal followers of Plextor now have something to exult over as the company has rolled out new models of external optical drives.
Not only willing to please its fans, the company surely pursues pecuniary goals, too. When its competitors are receiving profits from their external DVD-burners, it would be unwise not to offer alternative products. Considering the reputation of the manufacturer, these alternatives will surely find their target audience.
In this review we will discuss one of the new external drives from Plextor; it has a standard form-factor.
Its case made of black plastic, the device has a cute and individual appearance. On the front panel, under the disc tray, there is an eject button, a LED operation-mode indicator, and a few symbols indicating the device class. The manufacturer’s name and labels for the connectors on the rear panel are located on the top of the drive. A LED-based power indicator is built in between the top and right panels. The back panel carries two FireWire and one USB port, an interface selection switch, a power connector, a power-on button, and a cooling fan.
Now, what about the technical characteristics of the drive? The model is based on the standard PX-750UF optical drive and has almost the same parameters as the result. The manufacturer specifies the maximum read speeds as 16x for DVD-ROM and 48x for CD-ROM media. DVD+R and DVD-R media can be read at up to 16x speed. DVD+R DL and DVD-R DL discs can be recorded at 8x (you need to update the firmware to use this speed with dual-layer DVD-R media). The maximum speeds for writing DVD+RW, DVD-RW, DVD-RAM, CD-R and CD-RW are 8x, 6x, 5x, 40x and 24x, respectively. The drive’s buffer is 2MB big. The access time is 130 milliseconds for CD and 140 milliseconds for DVD media. The drive supports USB 2.0 and IEEE 1394 interfaces. The following DVD media formats are supported: DVD-RAM, DVD-ROM, DVD-Video, Multi-Border, Multisession, DVD+VR, DVD-VR. And these are the CD formats supported: CD-DA, CD-ROM Mode-1, CD-ROM Mode-2, CD-ROM XA, CD-Extra, Photo-CD, Video-CD, Multisession, CD TEXT, CD-I, Mixed CD, and CD+G (read only). The dimensions of the device are 167.1 x 53 x 253.5 millimeters; its weight is 1.5kg.
The drive is accompanied with a power adapter, USB and FireWire cables, and two CDs with software. The contents of the “standard” CD are shown in the screenshots above. The PlexTools Professional program was described at length in one of our earlier reviews, so we won’t repeat it here again. The improved version of this utility – PlexTools Professional XL – is supplied for trial use only and it doesn’t differ much from the previous version. The difference mainly concerns the user interface. The “bonus” CD (its contents are also shown in the screenshot) contains some utilities to enhance the drive’s functionality. Most of these utilities are for a 30-day trial, though.
The average retail price of the drive is $210.
We used the following programs and utilities to explore the operational parameters of the drive:
The testbed was configured like follows:
I tested the drive in its default speed mode and connected it to the computer via a mainboard’s USB 2.0 interface.
Besides the two informational utilities available to the general public, we are also going to show you the data produced by the exclusive PlexTools Professional:
The screenshots show that this optical drive is a multi-format device supporting almost all hardware functions you may ever require, except reading CD+G. You can also see that far less than 2 megabytes of cache memory is actually available. PlexTools Professional also reported the offset at reading and writing audio CDs.
The only confusing thing was the maximum read/write speeds reported by the same program. It says CDs and CD-RWs can be read at 48x which is virtually impossible for the latter format. The write speed of 48x doesn’t conform to the declared 40x, either. In the default speed mode, which we used in our tests, the Nero CD-DVD Speed utility reported 40x for both writing and reading CDs. The maximum speed of 48x is usually enabled in Plextor’s drives by choosing the Speed Read option in PlexTools Professional, but the detailed speed characteristics of the drive shown on the manufacturer’s website declare 40x as the max CD processing speed:
By the way, the same numbers are printed on the drive’s own box, so there’s some confusion in the information supplied by Plextor. I even dropped in on the native site of the company where you can see that 40x speed is declared for CDs even if you don’t know the Japanese hieroglyphics. If you do know Japanese, here’s a screenshot with the drive characteristics from that website:
I can think of one explanation: Plextor is just selling drives with different firmware, in which the maximum CD processing speed is varied, on different markets.
As usual, I tested the drives in WinBench 99 using a molded CD-ROM and two its copies made on CD-R and CD-RW discs.
There’s a single flaw at the beginning of the graphs for the CD-R and CD-RW discs. Otherwise, the drive is blameless.
The table and the diagrams above tell us that the drive doesn’t offer an exceptional performance when processing CD media. The CD-ROM WinMark scores are rather average. Note that although the data-transfer graph for the CD-ROM had the most perfect shape, the measured access time proved to be the worst with that disc and higher than specified.
I use five CD media to perform these tests: a molded CD-ROM enclosed with a computer magazine, 700MB data CD-R and CD-RW discs recorded by Nero CD-DVD Speed itself, a likewise prepared 800MB CD-R, and an Audio CD. Unfortunately, the drive could not read the 800MB CD-R to the end, producing an error message.
The drive processes CD media well, except for the above-mentioned 800MB CD-R. It produces similar results and reaches a read speed of 40x with all the media types, including CD-RW (optical drives usually perform slower with CD-RW media).
Note that the measured access time is smaller than the specified value irrespective of the disc type.
The second group of tests is about DVD formats. I took seven discs to get a fuller picture of performance of the drive: a DVD-ROM with a video movie and its copies made on DVD-R (Digitex), DVD-RW (TDK), DVD+R (Fujifilm), and DVD+RW (Verbatim) discs. I also used a dual-layer DVD+R from RIDATA and a 3x Verbatim DVD-RAM.
The data-transfer diagrams betray no problems. The maximum speed was quite expectably achieved with the DVD-ROM. The drive had the lowest speed when processing the DVD-RAM – the transfer graph shows the DVD-RAM was being read at a constant linear speed.
Note that the measured access time is higher than declared with the DVD+R DL and DVD-RAM discs.
Exact Audio Copy and Nero CD DAE cannot “see” external optical drives, so I didn’t use these utilities in the current test session.
The Advanced DAE Quality Test helps determine hardware characteristics of an optical drive pertaining to the process of getting accurate copies of CD-DA media. Two CD-R discs prepared in Nero CD-DVD Speed are used in this test. One audio disc is normal; the other has defects of the surface, imitating your trying to make a copy from a long-used, bad-quality audio compact-disc.
The first screenshot is about processing the good audio CD. The average audio extraction speed is quite high; the resulting quality score is 100%. So, it seems the drive did its job well, but take note that it couldn’t read the lead-in and lead-out areas. The read offset is rather big, too, and differs from what was shown by PlexTools Professional which reported 408 bytes rather than 432.
The second screenshots shows the results with the bad audio CD. The drive did well here. The average track extraction speed is but a little lower than with the good CD. The number of errors is low, so it is no wonder the drive turns in a 100% quality score again.
The ability of an optical drive to process C2 errors at all and to process them efficiently is most important when it works with low-quality media. I ran the Advanced DAE Error Correction test with the bad Audio CD prepared in Nero CD-DVD Speed to check the drive’s ability to process errors that occur during the audio ripping process. The program determines how many C2 errors should be found by the drive and how many errors the drive actually finds and then produces C2 Accuracy and Quality Score parameters which reflect the efficiency of the hardware error-correction logic in the given drive. Unlike the previous test, this one not only tells how many errors occur as the drive is reading an audio CD, but also evaluates the drive’s ability to find such errors.
The screenshot with the results of the test illustrates the excellent performance of the drive here. There are few C2 errors and none of them missed. Of course, the program reports a 100% C2 Accuracy and gives the drive a nearly ideal Quality Score.
As the final step in this test session, I will burn a few DVD discs of various formats in the tested drive and check their quality. Of course, I can’t check the drive with all existing media and in all possible modes, but this test is anyway indicative of the burn quality the drive provides. I used Nero Burning Rom to record all the discs at their maximum rated speed (except for some situations mentioned below). The quality of the recorded discs was verified using a Lite-On SOHW-1653S drive with firmware CS0T. We traditionally use it to achieve comparable results from different test sessions.
As for the disc quality criteria, the ECMA standards for DVD-R/RW and DVD+R/RW media say that the total number of PI errors in 8 subsequent ECC blocks should not exceed 280. This is the first limiting value I will base my judgments upon. Then, an ECC block should not contain more than four irrecoverable PI errors (an irrecoverable PI error is referred to as PI failure by the CD-DVD Speed utility).
DVD discs that have no more than 280 PI errors per eight ECC blocks and 4 PI failures per one ECC block should be considered acceptable-quality media. Besides these criteria, you should also note how the errors are distributed along the surface of the disc. It is the worst situation when the errors exceed the acceptable limit on the entire surface, but single and short-time spikes of errors are less dangerous.
Of course, the more discs are recorded with high quality, the better for the tested drive, but keep it also in mind that besides the hardware properties of the drive, its firmware version has a big effect on the burn quality, too.
Sony’s DVD+R disc rated for 16x burn speed could only be recorded by the Plextor PX-750UF at 4x. Of course, this affected the quality of the resulting disc, which is more than satisfactory. The low peaks of errors of both types and the manner of their distribution on the medium indicate this. The result would be different, of course, if the drive had burned the disc at 16x.
Only a very carping person would find any faults with the quality of the TDK DVD+R which I recorded in the Plextor PX-750UF drive. The maximums of errors of both types, and especially of PI Failures, fit well within the limits described by the ECMA regulations. The burn quality is uniform throughout the entire disc, so this is almost an ideal disc. It will surely be readable in any optical drive.
We get different results with this recordable DVD from Verbatim. It’s all quite well on the first half of the disc, but the other half brings about a sudden surge of errors of both types. The level of PI Errors exceeds the ECMA limit then, so the disc can’t be considered as a quality one.
The 8x DVD+R from L-PRO isn’t satisfactory, either. The maximum of PI Failures doesn’t fit within the ECMA limits. The screenshot above shows that the acceptable burn quality on the most part of the disc surface is spoiled by the final stretch where there is a surge of errors of both types.
The second disc from Sony, this time a DVD-R, also couldn’t be written by the drive at its rated speed of 16x. Like with the other disc, only 4x speed was available. I guess the problem is in the drive’s firmware and may be corrected in future firmware updates. And of course, the burn quality we see here is different from what we would see if the disc had been recorded at its highest rated speed. The disc burned at 4x is blameless. The maximums of errors are far within the required limits. The burn quality is uniform throughout the entire surface.
The Plextor PX-750UF recorded the TDK DVD-R disc very well. The error-distribution diagrams show acceptable peaks of PI Errors and PI Failures. The top graph looks very impressive: the number of PI Errors there is close to the minimum you can ever hope to achieve in practice.
The Plextor PX-750UF doesn’t seem to like discs from Verbatim. The quality of this disc is non-uniform, and there are also unacceptably high peaks of PI Failures. It’s all normal with PI Errors from ECMA’s point of view, but we’ve seen better-quality discs above.
The recording quality of the Fujifilm DVD+RW disc is not exactly good because there are unacceptably high peaks of PI Failures. On the other hand, there are just a couple of such peaks here, so the disc is not downright bad.
The recording quality is not satisfactory here from the standpoint of the ECMA regulations. Peaks of PI Failures are far above the acceptable limit all through the medium surface.
The results we’ve got with this 4x Digitex DVD-RW disc are similar to those of the previous test. Again we see the level of PI Failures is much too high on the entire surface of the medium.
The recording quality with this disc is worse than with the other two tested discs from Verbatim. Much worse. The maximums of errors of both types, and especially of PI Failures, by far exceed the limits set by ECMA. This medium is likely to be absolutely unreadable.
The release of external DVD-recorders from Plextor is going to positively affect the market at large. I mean that tough competition is always good for the end-user as it leads to lower prices and better products. And people who stick to the Plextor brand can now buy an external drive from their favorite manufacturer.
And now I’ll try to sum up the pros and cons of the reviewed PX-750UF drive. The good comes first. The drive is nicely designed, especially if you like black-colored peripherals. Indisputably good is that the drive supports two interfaces, USB 2.0 and FireWire, giving you more connectivity freedom. The device supports all the media formats currently in use. The PX-750UF produced good discs in our burn quality tests, except for discs from Verbatim and for rewritable discs which are generally harder to burn well. On the other hand, it is clear that the drive’s firmware needs improvement as was indicated by the Sony discs which could not be recorded at their rated write speed. Another of the drive’s good points is its rich accessories typical of Plextor’s products, which include the functionality-enhancing utility PlexTools Professional. The drive’s accuracy at finding C2 errors must be acknowledged, too.
And now, some not quite pleasing facts. First, the price of the device is rather steep, traditionally for Plextor. Some users may want to consider cheaper alternatives. As for the hardware parameters of the device, there’s some confusion as to the CD processing speeds it supports. The different Plextor websites declare different speeds, but the speed of 40x it showed in our tests is quite sufficient for most users. The drive didn’t do too well in our audio-ripping tests. It has big read/write offsets (and the results of the tests do not coincide with what PlexTools reports) and couldn’t read the lead-in and lead-out zones. Some of the media I tried to burn in this drive proved to be of low quality, but as I mentioned above, this is probably due to some flaws in the drive’s firmware which will certainly be improved in the future.
So, that’s all we have to say about the PX-750UF external optical drive from Plextor whose market future is now entirely in your hands.