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Original Link: https://www.anandtech.com/show/270
Quick Look |
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Kenwood TrueX 52X |
The Good | |
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+ Hard drive
like transfer rates |
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The Bad | ||
- Relatively expensive
- Drive and discs get hot |
The CD-ROM is often one of the last pieces taken into consideration when buying or building a system and that is not incredibly unreasonable. After all, it seems like most of the time, the only time the CD-ROM gets used is to install software. As such, it's not too surprising to see all kinds of 8X or even slower drives laying around.
While it is possible to get by with such a slow CD-ROM, prices on drives have dropped so drastically that it is just not necessary to do so. Whether you just want your programs to install faster, or you would rather not put yet another 600MB full game install on your hard drive, a faster CD-ROM never hurts.
Starting with 4X drives, CD-ROM speeds were constantly being ramped up. Initially, increases in speed were gained by simply spinning the disc faster, which was successful for speeds up to about 12X.
Then someone got smart and realized that CD's were read using a constant linear velocity method (CLV), which means that the disc was spinning slower while reading the outer edges. This realization brought a new method, constant angular velocity (CAV), to read CD's. This meant that the disc was always spinning at the same rotational rate, regardless of what portion of the disc was being read.
That leads to data that is actually passing by the reading head faster on the outer portions of the disc, and thus higher transfer rates on the outer part of the disc. A by product of using CAV technology is that the drive motor does not need to change speeds, so access times are improved.
By simply implementing CAV, those 12X drives immediately became 24X "max" drives where the inner part of the disc was actually read at 12X and the outer part at 24X. Further increases in rotational speed have led to today's 50X "max" drives.
Unfortunately, data is written to a CD starting at the inside and discs are rarely filled to capacity. Thus, the max speed rating was not particularly meaningful. Further, the rotational speed required for a 50X drive is over 10,000 RPM, leading to major noise issues - some of those drives sound like jet engines while they are spinning!
Zen Research decided there had to be a better way...
Instead of just doing what everyone else had been doing for the past few years, Zen decided to take a totally different approach. Instead of just spinning the disc faster, they decided to use a totally revolutionary method that features multiple beams to read parallel tracks on the CD-ROM. Zen describes it best in their white paper as follows:
The Multiple Beam approach to illuminating and detecting multiple tracks uses a diffracted laser beam in conjunction with a multiple beam detector array. A conventional laser diode is sent through a diffraction grating which splits the beam into seven discrete beams, spaced evenly to illuminate seven tracks. The seven beams pass through a beam splitting mirror to the objective lens and onto the surface of the disc. Focus and tracking are accomplished with the central beam. Three beams on either side of the center are readable by a detector array as long as the center is on track and in focus.
The reflected beams return via the same path and are directed to the multiple beam detector array by the beam splitter mirror. The detector contains seven discrete detectors spaced to align with seven reflected tracks. Conventional detectors are also provided for focus and tracking.
With this technology, high performance CD-ROM drives can be made without such ridiculously high rotational speeds and without the use of CAV. The return to CLV has allowed for the replacement of the "max" part of the drive rating with the "TrueX" moniker.
Zen manufactures a component set consisting of optics and high speed ASICs. So far, only Kenwood Technologies who manufactures the 52X TrueX drive (as well as a 40X model), have picked it up. You'll also see these drives repackaged by Hi-Val and, more recently, they are included in some Compaq retail PC's.
In the package, you will find a quick installation guide, a full manual, IDE cable, and a CD-ROM cable. That is pretty much all you should need to install a CD-ROM drive, which are some of the easiest computer devices to install.
Drive Specifications Drive Interface Disc Loading Disc Readable Formats Disc Diameter Optical Beam Reader Data Transfer Rate Burst Data Transfer Rate Access Time (1/3 Stroke) Within 7 Track Band Data Buffer Eject Button LED Headphone Jack Volume Control Interface Connector CD-Audio Analog Out EIDE Settings |
General Specifications Installation Orientation Dimensions (W/H/D) Weight Power Supply
Reliability MTBF Warranty
System Requirements Minimum* Recommended (For Optimum Performance)
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The Test
The AnandTech test bed consisted of the following components:
- Intel Pentium II 400MHz
- Abit BH6
- 64MB Samsung Original PC100 SDRAM
- Matrox Millenium G200 8MB SGRAM
- Western Digital AC35100 - UltraATA
- Windows 98
The latest device drivers were used for all components. Tests were performed using Ziff Davis CD Winbench 99 and Testalabs CD Tach 98. The graphics mode was 1024x768 in 16bit color. Bus mastering DMA was enabled using Windows 98's built in PIIX4 driver.
CD-ROM Performance |
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CD Winbench 99 | CD Tach 98 | |||||||
Weighted Winmarks |
Inner
track Transfer rate |
Outter
track Transfer rate |
Access time |
CPU Utilization |
DAE | Random Access time |
CPU Utilization |
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Kenwood 52X TrueX | 1210 | 6.6MB | 7.5MB | 118ms | 3.4% | 11.8X | 98ms | 11% |
The advantages of Zen's multibeam technology are many. TrueX drives feature a (mostly) constant transfer rate across the entire disc and lower rotational speeds for quieter operation. The 52X TrueX rotates at about the same speed as a 9.5X drive and is thus incredibly quiet, while still providing hard drive like performance.
Multibeam technology provides solely for transfer rate increases, but does nothing for seek times. In fact, the return to CLV means that the TrueX drives have to change motor speeds as data is read from different areas of the disc, so access times are actually worse than many CAV drives. Within the seven tracks that are being read simultaneously, access time drops to a phenomenal 5ms.
Clearly, transfer rates are phenomenal and provide the hard drive like performance claimed by Kenwood/Zen. That 2MB buffer certainly did not hurt the scores either (most CD-ROM's have just 128KB - 256KB buffers).Digital Audio Extraction (DAE) was performed at approximately 12X and the drive reports extraction errors and corrects them in hardware for clean audio every time. That 12X number is just a bit higher than its rotational speed - maybe it cannot yet take complete advantage of multibeam DAE. However, note that 12X is still a very respectable DAE speed. Some drives cannot perform DAE at all or only do it at 1X.
It's also interesting to note that despite supporting only PIO Mode 4 or DMA Mode 2, the CPU utilization scores were excellent. A SCSI version will be available in the second quarter of 1999.
Quick Look |
||
Kenwood TrueX 52X |
The Good | |
|
+ Hard drive
like transfer rates |
|
The Bad | ||
- Relatively expensive
- Drive and discs get hot |
The Final Decision
Performance was as as advertised so it pretty much comes down to "Is it worth it?"
Well, the $120 price tag is significantly higher than almost any other (non-SCSI) CD-ROM out there. It is a tough decision - the fastest CD-ROM drive on earth, but at a price. And to top it off, there is above average digital audio extraction and extremely quiet operation. Once you have experienced a TrueX drive, it is hard to go back. For many, the quiet operation alone is enough to justify the added cost.
If you must have the best, go for the TrueX 52X. If you just need a CD-ROM for installing software, get something that costs less than half as much.