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CD-ROM performance is vital for most of us

• You can not increase the CD-ROM's access speed.
  However, increasing the size of its caches does improve performance.

• Be sure you use the correct driver, installed correctly.

• Consider using a CD-ROM accelerator


Use the latest driver, maximize both RAM available and the hard disk Cache, and perhaps use an accelerator

Use the Hard Disk

The first, and the easiest, way to improve CD software/games performance is to copy all the data across from the CD onto the Hard Disk, and run it from there. The Hard Disk may be slow, but it is many times faster than the CD-ROM drive.

Avoid running low on free Hard Disk space!


It is likely that the drivers that came with your CD-ROM have been updated (even if recently purchased!). You should check with the manufacturer to make sure you are using the latest version.

The newer driver will be faster, safer, and tweaked for better overall performance.

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Read-ahead Buffering

This buffer is used separately for your CD-ROM.

• Select (right-click) My Computer • Properties • Performance.
• In File System set both the CD-ROM
Supplemental Cache Size and
Optimize access pattern for
Use according to your needs (read next two items)
(These settings affect the buffer size up to a maximum of 1,238Kb)

How much Read-ahead to use?
When deciding on the amount of Read-Ahead to use, you need to remember that this cache operates dynamically; it expands (to the maximum), and contracts, according to need (in balance with the other memory needs at the time). If the CD-ROM is not used, then memory will not be allocated.

This cache (buffer) CAN be paged out (swapfile) to the Hard Disk - accessing from there will stiill be much faster that from the CD.

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Regular CD-ROM users

If you are a regular CD-ROM user (e.g. games), AND have sufficient RAM

• set Supplemental Cache Size to maximum
• in Optimize access pattern for select the highest speed CD-ROM available (even if you do not have that one!)

Non-regular CD-ROM users

If you are not a regular CD-ROM user, OR you have a RAM shortage

• set Supplemental Cache Size lower, to maximize your usable RAM
• in Optimize access pattern for select the correct speed for your CD-ROM

• Many multimedia programs do not reuse data and may perform better with a smaller cache.
A little experimentation may be necessary to achieve your optimum setting.

DVD: Digital Video Disc uses the Universal Disk Format (UDF) for its file system. This means the system cache, VCACHE, is used and there are no special cache settings for DVD.

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Accelerators work

If you are heavily reliant on CD-ROM usage then before you upgrade, think of a software solution. CD-ROM accelerator programs have been shown (independently) to boost overall drive performance by about 40%+.

You may have to sacrifice 20MB and 40MB of your hard disk space - to a cache of CD-ROM data that the program creates on your hard disk.

One such utility is Get it CD-Quick Cache ( v 3.10; 489 KB; Shareware ). "This is designed to improve the performance of any CD-ROM drive by storing frequently read data in fast RAM or on your hard drive. It uses advanced caching techniques for top performance and includes the utility Quickmon to show cache statistics in real time."

This Site has no experience with these utilities.

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Slave / Master

Remember: Two devices on different channels can not be concurrently 'active'. When on the same channel, one device is 'silent' while the other is 'active. Also channel-sharing devices work at the speed of the slowest device on that channel.

Avoid putting the CD-ROM on the same channel as a HDD. Doing so will cause deterioration in the performance of the hard drive:

1. If your hard drive and the CDROM are on the same EIDE channel, the HDD has to wait until a request to the CD-ROM has finished. CD-ROMs generally use lower PIO modes and are relatively slow performers. That Hard Disk's performance will be hit.

2. The CD-ROM is 16-bit device; the HDD is 32-bit. If a 16-bit and a 32-bit device share the same channel, the 32-bit is forced to operate as 16-bit (slower). HDD speed is vital to overall performance and should be allowed to operate optimally as a 32-bit device (faster).

When channel sharing is necessary, it is normal practice to set the CD-ROM as the slave device. However a minority of users claim that setting it as master enhances CD-ROM performance! You may need to experiment with your own system.

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Enable DMA

Enabling DMA (direct memory access) will not give you a notable increase in speed, but will take load off your CPU which is always helpful.

Not all CD-ROMs can enable DMA, or use it successfully, so results will vary. After enabling it try some games out. If it appears to take less time to start reading and the software/games seem to be running faster then it is working well.

The best way to check on its performance is to use CDCheck (see next)

To enable DMA on your CD-ROM drive:
Be prepared to return and disable DMA if it does not work satisfactorily.
Start | Settings | Control Panel | System | Device Manager | CDROM | your cd-rom | Properties | Settings
and enable MDA (if present)

Note:   Many CD-ROMs cannot deal with DMA bus mastering drivers, and problems may result if you try to enable Bus Mastering for a hard disk on a channel shared with a CD-ROM.

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You can compare your CD-ROM before/after a change, and identify your optimal settings, by running a benchmark utility such as CDCheck or CD-Check

Note:   A larger memory cache will only benefit those whose CD drive can avail of a larger cache.


Use a CD lens cleaner on your drive. Any dust, fluff, or dirt that touches the laser lens will slow down its access time. Cleaning it can speed it up dramatically.

Also keep your CDs and the tray clean - dirt gets transferred.

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CDGod driver(s)

CDGod is like a small generic driver for CD-ROMs, and should work with most CD drives. It creates a boot disk with loads of CD drivers, one of which should work for you.

If for some reason you are missing the correct driver, or yours is non-functional, then this may do the trick.

For better performance get the correct driver as soon as possible!

Get itCDGod (freeware, about 1MB)

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Gain access to the CD-ROM in Safe Mode

You may need this information if you are having problems installing Windows from CD-ROM, or if you are trying to determine if CD-ROM problems also occur in Safe Mode.

According to Microsoft:

" To make your CD-ROM drive accessible in Safe Mode, use the following steps:
NOTE: For this procedure to work correctly, real mode CD-ROM drivers must be installed. If you are unable to obtain and install the original real mode drivers for your CD-ROM drive, consult the manufacturer of your CD-ROM drive.

Microsoft then says you should go to a command prompt, type "win /d:m" (without quotation marks), and then press ENTER.

THPC suggests you should just pop in your Bootup floppy disk because it has the real mode drivers on it

. . . hasn't it!

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Mania? Well, Not quite!

You are not restricted to the maximum settings presented by Windows in the CD-ROM options - CacheSize, and Read-ahead (Prefetch). Both of these can be increased further and will improved CD-ROM performance when used under Windows. You will need lots of main memory for this.

Dedicated CD-ROM users, who are also Advanced Users, can read CD-ROM Mania (next) which shows how to further enhance these caches.

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Please remember that you alone are responsible for the consequences of any changes you make to your computer hardware or software.

Copyright © LarryM 1998-2015