Sep 27


Among diehard tweakers, the urge to squeeze out every last bit of performance from a computer is irresistible. As a result, even a casual web search turns up dozens of tips intended to help you improve performance in Windows.

Unfortunately, many of the Windows-tuning tips we’ve seen are of dubious value, and a few can actually hurt performance when indiscriminately applied. Some of these spurious tips are derived from techniques that worked with older Windows versions but are irrelevant now. Others are based on seemingly logical but erroneous extrapolations of how would-be experts think Windows works.

Page File Confusion

By far the most common instances of performance-related misinformation revolve around the subject of page files, also known as swap files. The following are some widely published myths about the proper configuration of virtual memory in Windows:

If your computer has a large amount of memory installed, you should eliminate your page file completely. This is incorrect. Although you can configure Windows so that it does not set aside any virtual memory, no reputable source has ever published benchmarks establishing any performance gains from doing so, and Windows simply wasn’t designed to run without a page file. If the goal is to conserve disk space, a more sensible strategy is to configure Windows to create a page file with a relatively small minimum size and monitor its usage over time to see how much virtual memory the operating system actually uses in daily operation.

Creating a page file of a fixed size improves performance. This is also bad advice. The logic behind this tip dates back to the earliest days of Windows. On 1990s-vintage hardware, dynamically resizing the swap file caused noticeable delays in system response and also resulted in excessive fragmentation. The memory management subsystems in Windows XP and Windows Vista have been tuned to minimize the likelihood of performance problems.

Prefetch Pros and Cons

To improve the speed of starting applications, Windows continually monitors files that are used when the computer starts and when you start applications. It then creates an index (in the %SystemRoot%\Prefetch folder) that lists segments of frequently used programs and the order they’re loaded in. This prefetching process improves performance by allowing the operating system to quickly grab program files.

A widely circulated tip of dubious value recommends that Windows users clean out the Prefetch folder and consider disabling the Prefetch function. Some sites even provide links to utilities that automate these functions.

Clearing out the Prefetch folder forces Windows to run programs inefficiently—but only once, since Windows rebuilds the Prefetch layout for a program the next time you run that program. Disabling the Prefetch function eliminates Windows’ ability to optimize program loading. In either case, it’s hard to find a logical reason why the tweak should result in a performance improvement.

Is it necessary to clear out the Prefetch cache occasionally to eliminate obsolete files and to minimize wasted disk space, as some websites claim? Hardly. A typical Prefetch folder uses 3-6 MB of disk space, and Windows flushes entries that are older than a few weeks. Our take? The developers responsible for the memory management subsystem of Windows did a remarkable job when they devised this feature. Don’t turn it off.

Shutting Down Services

We’ve also seen sites focusing on Windows services. One sensible piece of advice is to minimize the use of unnecessary background applications and system services. A few sites take this advice to an extreme, however, urging Windows users to shut down virtually all system services, including System Restore and Automatic Updates. We don’t agree that the average Windows user should perform this sort of radical surgery on Windows. In less-than-expert hands, the Services console is a minefield; some Windows services can be safely disabled, but indiscriminately shutting down services is a prescription for trouble.