Windows Prefetch Optimisation Myth Busted
Windows Optimisation myths are nothing new. About half a decade back, I had covered Windows XP optimisation myths. While some of these myths are harmless, others can have a negative impact on system performance and stability.
One myth that has been floating around for quite some time is related to the Windows prefetcher. Prefetching was introduced by Microsoft in Windows XP and was improved upon in Windows Vista and 7. The prefetcher is a part of the memory manager. Its main objective is to reduce program launch delays and speed up Windows boot process.
The prefetcher works by remembering what data is requested by a process during launch and tries to improve application launch times by serving the data in a more optimised fashion in the future. It does the same thing during system boot. It records the files and instructions requested during the boot process and uses this to reduce boot times.
The Windows prefetcher was designed to work on its own, without user intervention. Unfortunately, some pundits decided that they knew better. A popular belief seems to be that the prefetch folder accumulates junk over time and should be flushed periodically. This is not a new tip. In fact, it has been around since the days of Windows XP. Several experts have repeatedly debunked this myth, including Ryan Myers from the Windows Client Performance Team. Yet, the myth has managed to persist.
The reason why you should not delete the contents of your prefetch folder (WindowsPrefetch) is that, it cleans itself automatically. The prefetch folder contains a maximum of 128 entries and as a result if you don’t use an application for a period of time, information related to it will automatically be purged.
Deleting the prefetch folder is not only stupid but also counterproductive. The folks behind TuneUp Utilities performed some testing and found that deleting the prefetch folder had a considerable impact on system performance.
In short, don’t tinker with Windows prefetch algorithm. Do NOT clean your prefetch folder or perform some sort of prefetch optimisation – even if your trusted System Optimisation utility tells you to.