If you have some Windows XP clients that run slower than others, it could be due to some of the default settings located in the Performance Options dialog box. You can change the options in this dialog box to boost the performance of a Windows XP client. In this article, I’ll briefly examine the settings you can change to tweak Windows XP’s performance.

Performance Options dialog box
The most useful Windows XP performance-tuning options are on the Visual Effects and Advanced tabs of the Performance Options dialog box. You’ll find this box via the System Properties control panel by clicking the Settings button under Performance (Start | Control Panel | System | Performance | Settings). Figure A shows both the Visual Effects and Advanced tabs with the performance options you can easily modify.

Visual Effects tab
The Visual Effects tab is the easiest place to start when troubleshooting certain performance problems. By default, Windows XP enables visual effects, such as the “scroll” option for the Start menu. These effects consume system resources, though. If you’re troubleshooting a sluggish system, you can potentially improve its performance by choosing the Adjust For Best Performance option, which will disable many of these visual effects settings. Of course, you’ll lose the cool visual effects, but there’s always a tradeoff for performance.

Advanced performance settings
For troubleshooting something more than sluggish screen redraws, you’ll need to adjust the performance options on the Advanced tab of the Performance Options dialog box. There are three sections: processor scheduling, memory usage, and virtual memory. Each of these sections’ settings has a major impact on how your system operates.

Processor scheduling
The processor scheduling section controls how much processor time Windows XP devotes to a program or process. The processor has a finite amount of resources to divide among the various applications. Choosing the Programs option will devote the most processor time to the program running in the foreground. Choosing Background Services allocates equal processor time to all running services, which can include print jobs and other applications running in the background. If your users complain about slow-running programs, you could try setting the processor scheduling to Programs.

On the flip side, if users complain that print jobs never print or are very slow to print, or if they run a macro in one application while working in another, you may want to assign equal time slices (called quanta) to each process by choosing the Background Services option. If you use the Windows XP machine in question as a server, you’re better off choosing the Background Services option.

Memory usage
The next section, memory usage, details how Windows XP uses system RAM. The first option in the section, Programs, allocates more RAM to running applications. For desktop systems with very little RAM, this selection gives the best performance. In systems with less RAM, you need to devote as much RAM as possible to just running Windows and your applications. For a server or a desktop with a lot of RAM, however, choosing the System Cache setting will yield better performance. When set to System Cache, the system will use most of the available RAM as a disk cache, which can result in major performance improvements on systems that depend on disk I/O.

Virtual memory
Finally, there are a number of settings in the virtual memory section that affect how Windows XP performs. Virtual memory is an area on the disk that Windows uses as it if were RAM. Windows requires this type of system in the event that it runs out of physical RAM. The virtual memory space is used as a swap space where information residing in RAM is written to the virtual memory space (also called the page file or swap file) in order to free RAM up for other processes.

When the system needs the information in the swap file, Windows puts it back into RAM and writes something else out to the disk in its place. Figure B shows the virtual memory settings for my laptop.

Windows XP has a recommended default page file size of 1.5 times the amount of system RAM. Since I have 1 GB of RAM in my laptop, the recommended size is 1.5 GB, although I only have 768 MB currently allocated for this purpose. I allow the paging file to grow as needed, up to a maximum size of 1.5 GB. You can also choose to let Windows completely manage this file, or to have no file at all. I highly recommend that you do not remove the paging file because you’ll experience a noticeable degradation of system performance without it.

One way to boost system performance is to place the paging file on a separate physical hard drive from the operating system. The only caveat is if the second drive is slower than the primary drive, you’d want to leave the paging file where it is.

You can also span the paging file across multiple disks to increase performance. To make changes to the virtual memory, click the Change tab on the advanced performance options screen, make your desired changes, and click Set. Any changes you make won’t take effect until you reboot the machine.

Power users tip
If you want to get every last ounce of power out of your machine but you don’t want to sacrifice any unnecessary disk space, you can use the Windows XP performance monitor to see how much of your paging file is taken up during normal usage and adjust its size accordingly. For example, if you have a 1-GB page file, but only 40 percent of it is used during normal operations, you may want to set it to 512 MB instead. You can gather this information by watching the % Usage and % Usage Peak counters for the paging file (see Figure C).

I only recommend these changes if you have time to tinker. Most of the time, the operating system’s recommendations will work just fine.