Microsoft KB Archive/141368

= Poor Performance from CD-ROM-Based Program =

Article ID: 141368

Article Last Modified on 1/19/2007

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APPLIES TO


 * Microsoft Windows Millennium Edition
 * Microsoft Windows 98 Second Edition
 * Microsoft Windows 98 Standard Edition
 * Microsoft Windows 95

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This article was previously published under Q141368



SYMPTOMS
When you run a program that accesses a CD-ROM drive, you may notice that the program is not performing optimally. You may notice slow data transfer in a business or reference program, or skipping or slow audio and video in a multimedia program.



CAUSE
This behavior can occur when the Supplemental Cache Size and Optimize Access Pattern For settings are not be set correctly for your CD-ROM drive.



RESOLUTION
To resolve this issue, follow these steps improve your CD-ROM drive's performance:


 * 1) Click Start, point to Settings, click Control Panel, and then double- click System.
 * 2) On the Performance tab, click File System.
 * 3) Click the CD-ROM tab.
 * 4) Move the Supplemental Cache Size slider to the right to allocate more random access memory (RAM) for caching data from the CD-ROM drive or to the left to allocate less RAM for caching data.

Note that many multimedia programs perform better with a smaller cache because these program tend not to reuse data.
 * 1) For reading continuous data, such as .avi files, use a higher setting in the Optimize Access Pattern For box. For reading random data, increase the Supplemental Cache Size setting and decrease the Optimize Access Pattern For setting.
 * 2) Click OK, and then click Close. When you are prompted to restart your computer, do so.

NOTE: If you are using real-mode drivers for your CD-ROM drive, these settings have no effect.



MORE INFORMATION
The supplemental cache is used to hold path table, directory, and file information. It is a passive cache holding data that has been accessed and may be accessed again.

The Optimize Access Pattern For setting is based on a 64K cache (single- speed read ahead plus 14K random access cache). This is incremented in 50K increments depending on the CD-ROM drive speed. It is an active buffer storing data initially read from the CD-ROM.

The default cache size is not based on the CD-ROM drive, but on the amount of RAM in the computer, as follows:


 * For computers with less than 8 MB of RAM, the default setting is single-speed read ahead cache (50K) + small random access cache (14K).
 * For computers with from 8 to 12 MB of RAM, the default setting is double-speed read ahead cache (100K) + medium random access cache (512K).
 * For computers with more than 12 MB of RAM, the default setting is quad-speed read ahead cache (200K) + large random access cache (1024K).

Keywords: kbenv kbfaq kbhardware kbprb KB141368

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