A CD-ROM-based video should run as smoothly on your PC monitor as a VHS tape does on your TV screen. Jerky video playback can ruin a presentation or debilitate a fast-paced game. Does video playback on your system seem less than fluid? Here's how to improve your view.

If you have a hot new Pentium III PC and a cutting-edge graphics card loaded with RAM, most videos should run flawlessly. But older Pentiums and even some Pentium II systems equipped with less RAM and weaker graphics hardware may have trouble playing full-screen videos. And if your CPU speed is below 166MHz, you'll need faster hardware.

If you can't afford a new system now, at least add a new graphics card with a minimum of 8MB of on-board RAM.

Here are some other ways to make the most of your existing hardware:

Check your cache settings. Your CD-ROM drive stores data in RAM cache, so make sure the cache size is maximised. Right-click the My Computer icon, select Properties, click the Performance tab, and then click the File System button. Next, bring forward the CD-ROM tab in the File System Properties box, and change the 'Supplemental cache size' setting in that box to 'Large'.

Caption: You can maximise your video performance by increasing
your CD-ROM drive's RAM cache properties

Play from the hard drive. If a video file isn't playing smoothly from a CD-ROM, try copying it to your hard drive, which normally goes faster than your CD-ROM drive. If you're running an entire multimedia application or game from a CD-ROM and your system has a multi-gigabyte hard drive, consider copying the entire disc to the hard drive temporarily.

Defrag your hard drive. Run Windows' Disk Defragmenter (Start-Programs-Accessories-System Tools). Multimedia files will play much faster when they've been stored in a continuous block of disk space.

Update your DirectX drivers. The term DirectX refers collectively to a group of several distinct application programming interfaces that streamline the flow of multimedia video and sound data between Windows and your PC's hardware. Since the DirectX package is an integral part of the Windows operating system, installing the latest version (DirectX 6.1) can substantially improve multimedia performance. Unless you've purchased your PC in the past six months, you're probably using DirectX 5.0 or earlier. Determining the precise identity of your installed version is quite easy. If you have DirectX 5.0 or later, the utility program dxtool.exe ù which you can find in your PCs \Program Files\directx\setup folder ù will tell you so. If you have something older, your best bet is to install DirectX 6.1 over the current version.

Caption: Which version of DirectX are you using?
Dxtool.exe will tell you

Windows 98 users can get the upgrade by clicking the Windows Update Wizard on the Start menu. The wizard examines your system and offers an automatic DirectX upgrade if needed. If your browser doesn't support this wizard or if you use Windows 95, download DirectX 6.1 from this monthÆs cover CD.

Another common way to install DirectX is from a new multimedia or game CD-ROM that contains the DirectX setup program. But be wary of this approach. Not all installation routines check to confirm that they are loading a newer version.