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Appeared on: Tuesday, June 25, 2002

1. Introduction

ASUS CRW4816A IDE CD-RW - Page 1

The first 48x P-CAV recorder is here!

- Introduction

The race for achieving the highest ever recording/re-writing speeds has been something that fascinates users and pushes manufacturers to adopt new technologies. After the 40x recording speed category a new star rises up at 48x recording speed. In order to achieve such high speeds, manufacturers adopt other technologies than Zone-CLV. P-CAV and CAV are the answers for such speeds and ASUS is the first manufacturer to offer not only CAV but also P-CAV 48x recorder among with increased re-writing speed (16x) and fast reading (48x). What we can expect from this proposal? Is really the ASUS CRW4816A the fastest writer, re-writer, and reader with so many other 40x recorders around?

- Features

The drive supports 48x writing (P-CAV), 16x re-writing (CLV), has a 2MB Buffer and includes "FlextraLink", "FlexSpeed" and "DDSS II" technologies. As ASUS explains:

., prevents users from buffer underrun problems caused by an empty data buffer, thereby eliminating the creation of unusable discs. Throughout the recording process, FlextraLink consistently monitors the data buffer status to ensure best recording quality. Once the available data drops below 1% of the total buffer capacity, FlextraLink suspends the recording and sets a marker at the last written position to avoid recording blocks. As soon as enough cache data is refilled in, the pickup head repositions itself to the marker and restarts the recording. FlextraLink uses minimal system resources so the PC remains full operational and available for other applications even during recording process.

The DDSS II is an enhanced follow-up to the first generation Double Dynamic Suspension System developed by ASUS. The DDSS technology is designed to minimize the vibration caused by the spindle motor and resonance between components as well as the drive and PC cases. DDSS II makes tracking and focusing even more precise, and successfully reduces the vibration and noise caused by high revolution of the spindle motor.

enhances accuracy and reliability when writing/re-writing across a broad base of certified media. It continuously monitors the recording media and sets the optimal writing speeds to ensure best recording quality. The built-in proprietary AI Auto Speed Adjustment Technology helps the driver function in the best status when reading across a broad base of certified media in different formats. It not only continuously monitors the reading media but also sets the optimal reading speeds. The latter greatly saves power and prolongs driver's life.

The exact writing speeds are 4x, 8x, 12x, 16x (CLV), 24x, 32x, 40x and 48x (P-CAV). ASUS states in the retail box that the 48x writing speed is CAV, but our tests showed its P-CAV, even faster.

The re-writing speeds are 2x, 4x, 8x, 10x, 12x and 16x (CLV) and the maximum reading speed reaches 48x (CAV). All known writing modes are supported (DAO, SAO, TAO and RAW), overburning . Mt. Rainier is officially supported from ASUS with the new drive and behind all these there is MediaTek's chipset that enable hardware EFM correction.

Below are the specifications as found in the retail box. Notice that ASUS says 48x (CAV) while our tests showed 48x (P-CAV) recording technology:

- CAV vs. P-CAV

CAV features three main charateristics:

CAV recording technology is also known as Full CAV. A CAV drive maintains a consistent rotation speed that results in different transfer rates. The linear velocity increases gradually as the read head move across the inner area of the disk to the outer area. A CAV drive also features minimum recording time and higher average recording speed.

The read head of a Z-CLV drive stops writing data, and buffer underrun happens every time when the motor changes speeds. Linking technologies, such as FlextraLink, BURN-Proof, JustLink, SafeBurn, to name a few, activates when buffer underrun occurs. On the other hand, no extra links will be produced during the recording process of a CAV drive that runs at a constant rotation speed, allowing a smooth transferal to higher speeds. Recording time is therefore greatly reduced, while average recording speed improves significantly.

P-CAV (Partial Constant Angular Velocity) Recording Technology

P-CAV recording technology is a cooperation of CLV and CAV that offers a stable and reliable way to record data. The transfer rate will continue to increases until the drive reaches its maximum writing speed, and then maintains a constant rate comparable to that of CLV technology. A P-CAV drive is considered by many to be an ideal solution for Audio CDs and pre-mastering a disk for mass duplication. The technology also brings stable recording quality since no links are produced during recording process.

- 48x recording speed

As we mentioned earlier, ASUS CRW-4816A is the first 48x recorder that supports not CAV but P-CAV. This implementation is probably faster than other 48x full CAV recording technologies. In the Nero graph chart, the green curve refers to the drive's transfer rate, while the yellow curve represents motor speed:

As Nero CD Speed reports, the drive starts writing at 23.17X and gradually reaches 48X speed at 66mins. The drive keeps that speed until the end of the disc. Using an 80min disc you maximize the average recording speed to 38.36X, which is the fastest, we measured in our labs. Note that this is the theoretical average recording speed. As our tests showed, the final recording times are not exactly the same as we were expecting.

Using various media, we witnessed changes in the average recording speed from 38.36X down to 37.98X:

The 40x (P-CAV) recording speed is also very fast with 35.75X average speed:

2. Installation/Package

ASUS CRW4816A IDE CD-RW - Page 2

- The package

The retail kit we tested contained: the drive, 1 piece of ASUS 80min 48x CD-R blank (manufactured by Acer, 97m 22s 67f), 1 piece of ASUS 80min 4-16x HS-RW blank (Acer 97m 22s 62f), audio cable and mounting screws. The software supplied with the drive was Nero Burning ROM v5.5.8.2 and Ahead InCD v3.27 (for packet writing use).

The drive came with v1.00 firmware revision installed and we hope this time that ASUS will support further its drive with firmware updates. So far there were not released any newer firmware for ASUS 32x and 40x recorders. We don't know yet whether ASUS CRW-4816A comes with a 2-year warranty (only in Europe) or not. Lastly as the package says the drive is "XP" compatible which was confirmed from our test results, since the drive worked without any problems in UDMA-33 mode.

On the front of the drive there are the "ASUS", "HS-RW" and the "48x16x48" logos. You will also find only two leds, the eject/play buttons and the headphone input jack/volume selector:

In the rear panel of the drive we will find the usual connectors (IDE interface, power), the jumpers for making the drive Master/Slave, the SPDIF output connector and the analog/digital output connectors. The 3 jumpers at the left are used to setup the drive's working mode, PIO-4Mode (default) or UDMA33. For setting up the UDMA33 mode you just have to remove the middle jumper:

- Inside the drive

After removing the bottom screws we can see the internal of the drive:

The drive is based upon MediaTek chipsets. Below are the MediaTek chipsets from the ASUS 48x and 40x drives:


In case you wonder if you can use the firmware from ASUS CRW4816A to the ASUS CRW4012A in order to gain the higher recording speeds you will be disappointed, unlike with LiteOn recorders...

- Installation

ASUS CRW-4816A was installed as a Master in the secondary IDE BUS. The drive worked in UDMA33 mode and after booting, identified itself as "ASUS CRW-4816A". We used WinXP for the recording, reading tests and the DMA was automatically enabled.

The drive is a June 2002 model with firmware revision v1.00 installed. We used the latest build of Nero (, InCD (3.31), and CloneCD ( for our recording tests.

ASUS CRW-4816A will automatically reduce the maximum writing speed (48x) when it detects lower quality media for burning. The pictures below come from Nero when blank media was inserted. The drive with firmware v1.00 supports limited media for the 48x recording speed, something that will disappoint some users who would wish to write all their media at the maximum speed:

3. Data Reading Tests

ASUS CRW4816A IDE CD-RW - Page 3

Data Tests

- Pressed CD results: (Click to see the CD Speed Graph)

At the Nero CD Speed test with PlexTools pressed disc, ASUS CRW4816A has the second best performance, below CyQve 4048, with 37.29X.

In the Seek times test, ASUS CRW4816A has the second best performance with 89ms, while TEAC CD-W540E sets new standard with 70ms.

- CDR Media: (Click to see the CD Speed Graph)

With CDR media, ASUS CRW4816A gets again the second place with 38.08X.

With CD-R media, the seek times of the drive rises up to 110ms. TEAC CD-W540E still holds the first place with 73ms.

- HS-RW media: (Click to see the CD Speed Graph)

For the RW tests we used the attached ASUS 80min 16x media written at 16x. The ASUS CRW4816A had problems reading the media as the CD Speed graph shows. The same media with other drives read perfectly, that leads us to the conclusion that its a bug of the CRW4816A drive:

The drive cannot be compared with other drives due to its low performance. The maximum reading speed of CRW4816A drops at 32x when HS-RW media is inserted:

4. CloneCD Reading Tests
ASUS CRW4816A IDE CD-RW - Page 4

CloneCD Reading Tests

- Procedure

We used CloneCD (v4.0.1.6) and 4 original CDs - Serious Sam 2 (SafeDisc 2), Desperados (LaserLock 2), V-Rally 2 Expert (SecuROM 2) and NBA Jam Extreme (PSX) - in order to test the reading time of the drives. We also tested the reading performance with backups of the original CDs, since the reading speed varies between original and backup media. The following pictures show the drive reading/writing capabilities as CloneCD reports:

- PSX Pressed Media

ASUS CRW4816A is the faster reader in this test with only 46secs:

- SafeDisc 2 Results

ASUS CRW4816A is the faster reader among the other drives and can make an image of SafeDisc 2 protected discs at only 3mins.

- LaserLock 2 Results

With LaserLock v.2 protected CDs, ASUS CRW4816A is again the faster reader with only 5mins for both pressed and CD-R backups.

- SecuROM Results

All tested drives can read SubChannel data from Data/Audio tracks. The faster drive comes from CyberDrive. ASUS CRW4816A gets the second position with 2527.70Kb/s.

5. DAE Tests

ASUS CRW4816A IDE CD-RW - Page 5

DAE Tests

- DAE features

- Pressed AudioCD results

ASUS CRW4816A reaches the 48x DAE ripping speed with either CD-R or pressed Audio discs. The drive would have won the first place this test, if CyberDrive wasn't present. Its average reading speed is 34.1X:

- CDR AudioCD results

With CD-R media, ASUS CRW4816A improved its reading performance and now gets the first place with 34.7X:

- EAC Secure Extract Ripping mode

For each drive we used the build-in detection function:

Tested Drives
Average DAE Speed (X)

- Advanced DAE Quality

All tested drives got a 100 score (best), except from CyberDrive CW-078D, in the Nero CD Speed Advanced DAE test. The ASUS drive has 33.36X average reading speed. It can also read CD-Text and SubChannel data as Nero CD Speed test reports:

- CD-Check Audio Test Disc
Error Level

ASUS CRW4816A drive reached the forth level of CD-Check test disc. The drive didn't produce any pops during the playback process until that level.

- Bad CDR Media results

The disc has fingerprints and includes light scratches, enough in order cause problems to most of the tested drives. We used CD DAE 99 software to rip the whole disc (756539616 sectors) and the results are posted in the following table:

Average Speed (X)
Errors Of Total Disc (%)
Drive locks after test disc inserted!

The drive refused to read the test disc. It locked after we inserted disc, and PC reboot was required to eject the media.

- Ripping 90 and 99mins AudioCDs
Tested Drives
Ripping up to
Cannot rip disc contents

- Reading/Ripping Protected AudioCDs

For the test procedure we used 2 protected AudioCDs, which we tested in both recognition and ripping (with CD DAE & EAC) processes:

* Pressed AudioCD with Sony Key2Audio (Celine Dion - New Day Has Come)
* Pressed AudioCD with Cactus Data Shield 200 (Natalie Imbruglia - White Lilies Island)

Cannot recognize the disc contents
Can recognize the disc contents but cannot rip!

The ASUS drive cannot "handle" protected Audio discs. In the case of Key2Audio disc, cannot recognize the inserted disc and with CDS200 even it recognizes correctly the Audio tracks, it cannot rip them.

6. CDR Tests
ASUS CRW4816A IDE CD-RW - Page 6

CDR Tests

- Procedure

We tested the ASUS drive with latest version of Nero/CloneCD. We used various media for our tests: Mitsubishi Chemicals 80min 40x certified, Mitsui 80min 32x/40x certified, Taiyo Yuden 80min 32x/40x certified, Philips 80min 40x and various HS-RW media. We burned CDs at almost all recording speeds from 16x up to 48x using the SAME amount of data for all tests. The posted recording times are the best we had from our test results. Using other media can increase the final burning time.

Currently with firmware revision v1.00 you can write up to 48x with the following media (from our tests):

Media from Mitsubishi Chemicals 40x/48x are only allowed to be written up to 24x and Hitachi-Maxell 80min 40x only up to 32x. Check the writing quality tests for details conserning drive's media compatibility

- Recording Tests

For all the recording tests, we used slightly more than 80min data (80:01:47). The CyQve 4048 has the third best recording time for the 16x writing speed. The Philips and Samsung SW-240B have the highest time with 335secs:

ASUS CRW4816A is the faster recorder above 16x recording speed due to its P-CAV recording technology. At the 40x writing speed, finishes first with 161secs, while the second faster drive from CyberDrive, follows with 184secs.

You may wonder where are the results from the 48x recording speed. The truth is that we are confused since the drive made the same recording times for the 40x and 48x speeds (2:41)secs as the following Nero screenshots prove. If we consider the drive's theoretical average writing speed, the recording times should be lower than what we have seen:

- Overburning Tests
Tested Drive
Writing up to

- CD-Text Results

ASUS CRW4816A can read/write CD-Text without any problems.

- CloneCD Writing Tests

The CloneCD v4.0.1.6 reports that all drives support the DAO-RAW feature. For the EFM correction (SD2 test) we used 'Serious Sam - The Second Encounter" and "Medal Of Honor" game titles. We performed both software/hardware EFM corrections test. The drive supports both modes (hardware and software), making it very appealing for advanced users. The drive doesn't limit its recording speed under DAO-RAW mode and writes up to 48x, with of course the proper media.

Tested Drives
DAO-RAW writing speed
Software EFM Correction
Hardware EFM Correction
Yes ( v2.50.021+)
Yes ( v2.50.021+)

7. Writing Quality Tests
ASUS CRW4816A IDE CD-RW - Page 7

Writing Quality Tests

We used many media and burned them at various recording speeds with the ASUS drive. The produced CDs, were measured from DigitalDrives and results are illustrated in the following tables.

- 32x writing speed (firmware v1.00)
Average Burning Time (mins)
Taiyo Yuden 80min (32x)


Hitachi-Maxell 80min (40x)
Prodisc 80min (32x)
SmartBuy 80min (32x)

- 40x writing speed (firmware v1.00)

Average Burning Time (mins)
Mitsui 80min (40x)
Imation 80min (32x)

- 48x writing speed (firmware v1.00)
Average Burning Time (mins)
Imation 80min (32x)
(under DAO-RAW with CloneCD)


Philips 80min (40x)
Philips 80min (40x)
Taiyo Yuden 80min (40x)
Philips 80min (24x)
Imation 80min (32x)

ASUS 4816A has a really small list of supported media for 48x writing. From our test discs, only the Philips (Ritek), Imation (CMC Magnetics) and Taiyo Yuden media were allowed to burn at the maximum speed, with however not very good results. Only with Taiyo Yuden 40x media, the drive produces good results. With the rest media, high C1 error rate and even C2 error occur making the produced discs un-readable.

At the 40x recording speed, we had a strange result with Mitsui's 40x media. Nero reported 2:41mins, exactly the same for the 48x writing speed. We are not so sure if the results should be considered as 48x or 40x, but probably they show the 40x speed. Future firmware upgrades can improve the supported media list.

Below are some graphs from various media written at various speeds:

- Imation 80min 32x burned at 40x (P-CAV) recording speed.

The C1 error rate is increased after 35mins and 60mins, C2 errors are present. The error rate goes in normal levels after 70mins:

- Imation 80min 32x burned at 48x (P-CAV) recording speed.

The C1 error rate increases after 35mins towards the end of the disc. No C2 errors are present, making the disc readable.

- Philips 80min 40x burned at 48x (P-CAV) recording speed (first disc).

The C1 error rate increases after 50mins towards the 70mins, lowers between 70-75mins and is increased again at the end of the disc. No C2 errors are present, making the disc readable.

- Philips 80min 40x burned at 48x (P-CAV) recording speed (second disc).

The C1 error rate stays low until 60mins. After 70mins error rate raises and C2 errors are present making the disc partial un-readable.

- SmartBuy 80min 32x burned at 32x (P-CAV) recording speed.

The C1 error rate is high during the first 30mins and drops after 40mins. C2 errors are present between 22 and 32mins making the disc partial un-readable.

8. HS-RW/Packet Writing Tests

ASUS CRW4816A IDE CD-RW - Page 8

RW-Packet Writing Tests

ASUS drive supports 16x re-writing speed only with specific media (based upon ACER chemicals). The test results were very good since the drive finished the burning at 5:00mins, and gets the first place:

The writing quality of the written disc can be considered as good since the total errors are within the Orange book standard:

- Packet Writing Tests

We used Ahead InCD v3.31 for the packet writing tests with the LiteOn HS-RW media. The formatted disc had 534mbs of free space. We copied a 403 MB file (403.147 kbs) from a Hard Disk (on the same PC as the writers) to the formatted RW media using Windows Explorer (we dragged and dropped) and we completed the test twice to eliminate any possible time measurement faults and user errors:

The best performance comes from the CyberDrive. The ASUS CRW4816A comes second with 11.28X average writing speed, while the rest drives stay behind since they have lower re-writing speeds of 12x. The ASUS drive stays below also during the reading under packet writing format with 12.8X.

- Mt. Rainier Tests

For testing the Mt. Rainier performance of the ASUS CRW4816A, we used was WriteCD-RW! by Software Architects. With several tested media, the drive locked after it finished writing. After rebooting the disc was empty. This indicates that ASUS's Mt. Rainier implementation needs improvement...

9. Conclusion

ASUS CRW4816A IDE CD-RW - Page 9


Positive (+)

Negative (-)

- First drive that supports 48x P-CAV writing speed
- 16x re-writing speed
- Supports "FlextraLink", "FlextraSpeed" and DDSSII technologies
- Drive is less noisy than Zone-CLV recorder ( DDSSII system)
- Very fast DAE ripping speeds
- Very good CloneCD reading performance
- Supports DAO-RAW writing (48x)
- Supports software & hardware EFM correction
- Supports reading/writing of SubChannel Data
- Supports CD-Text (reading/writing)
- Supports Overburning (up to 99mins)
- Supports UDMA33 connection interface
- Complete retail package (Nero, 80min HS-RW media)

- Writing quality needs improvement with various media!
- Supported media list for 48x speed is limited!
- Mt. Rainier is supported but...
- Cannot recognize written 99min CDs
- Cannot "handle" any protected Audio Disc
- Didn't recognized our BAD DAE disc test disc

ASUS CRW4816A is the first recorder with the fastest available now recording/re-writing speeds. It supports 48x writing (P-CAV), 16x re-writing (CLV) and 48x (CAV) among with "FlextraLink", "FlextraSpeed" and DDSSII technologies. Let's see drive's positive and negative points.

ASUS CRW4816A supports definitely the fastest recording speeds, for now until other 48x recorders arrive in our labs. The secret is the high initial recording speed of 22-23X that makes the drive writing almost CLV at 24x and P-CAV for the rest speeds. The re-writing speed is also very good but supported with limited media. The DAE ripping speeds are very good, DAO-RAW is supported and the drive supports hardware EFM correction that will be useful for many users who wish to backup their protected discs.

On the negative side, we can list the drive's limited media support for both 48x (P-CAV) and 16x (CLV) speeds, the very bad writing quality with specific media brands and the complete lack of protected Audio discs support. Lastly, even Mt. Rainier is present doesn't seem to work as it should be....

The price of the drive would be an important issue for possible buyers and currently you can find the drive at $.... In order to make safe decision we have wait until a new series of recorders arrives that would support such high (or even higher) recording/re-writing speeds.

PS. The mentioned problems could be corrected with future firmware upgrades, which however is not sure since ASUS in past hasn't released any newer firmware for its 32x and 40x models. We hope that this will not be repeated one more time...

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