ASUS High-Speed CD-ROM Drive User’s Manual
Cannot achieve the maximum data transfer rate performance specified for the CD-
1. If you are using a benchmarking utility, it may be old.
2. The disc is not full.
3. Given the signal quality issues with PIO Mode 4 transfer rates in some systems
and such variables as error correction, caching, processor overhead, and rota-
tional speed, higher transfer rates may not be achievable with the default trans-
fer mode. Thus transfer rates may be lower.
4. The disc you are playing may not be in a CD-ROM or CD-ROM format.
1. Upgrade your benchmarking utility to one that supports tests on the outer tracks
of your drive. Your CD-ROM Drive uses Constant Angular Velocity (CAV)
technology, wherein the spindle motor is running at the same velocity, while
the drive is accessing data at the inner or outer tracks. In this way, the drive will
achieve lower data transfer rates at the inner tracks and higher transfer rates at
the outer tracks. Thus using some or older benchmarking utilities, such as
WinBench 96, will give lower data transfer rates because these utilities use the
drive’s inner tracks for its performance tests.
2. A disc will occupy only the inner tracks when it is not full. Thus, because of the
way your CD-ROM Drive accesses data (see preceding explanation on CAV
technology), the drive will achieve lower data transfer rates. Use a full disc if
possible to get the maximum transfer rate from your drive.
3. Change the transfer mode of your CD-ROM Drive to Multi-word or Ultra DMA
Mode to maximize its capability.
• For DOS, see Transfer Mode under II. Software Installation for more information.
• For Windows 95 or Windows NT, Bus Master driver must be installed. Unless
your computer dealer installed the driver when you bought it or your mother-
board supports Bus Master mode, Windows will not use bus mastering for your
– Double-click My Computer | Control Panel | System | Device Manager |
CD-ROM controllers. If you are using bus master, PCI Bus Master will be
displayed. If not and your motherboard has the new PCI controller chipsets
from Intel, for example, the 440BX, but does not have a CMOS setting for
Bus Master mode, you may have to get the driver from Intel. Check with
your dealer for more information.
• If you do not have Bus Master driver under Windows 9x, double-click My Com-
puter | Control Panel | System | Device Manager | CD-ROM, right-click
ASUS CD-Sxxx and then click Properties | Settings. Under Options of the
Settings tab, click DMA to enable DMA Mode.
4. Your CD-ROM drive reads data at different speeds depending on the disc format.
Your CD-ROM drive performs at its best when it is reading a CD-ROM or CD-
ROM format disc. With other formats, such as Audio CD or Video CD, data trans-
fer rate performance may be slower than the maximum rate performance specified.
Cannot display the directory on an audio CD disc with the DIR command.
The DIR command does not work with audio CD discs while in DOS. You can use
the command, however, to display the directory on a data CD.
NOTE: You can use the DIR command to display the directory on an audio disc while in
Windows using the command prompt or MS-DOS Prompt. Refer to your Windows manual on
how to find the command prompt.