Does the Prefetch folder play any role in optimizing the performance of Windows and applications. Prefetch what kind of folder can I delete?

Hello, dear friend! Most recently, we looked at the topic of deleting temporary folders. There I talked about various folders, including Temp, in which garbage accumulates over time. These junk files needs to be cleaned. and published it, but as it turned out, not everything. I found an interesting folder that many people saw, but were afraid to delete something in it. This folder is called “Prefetch” and is located inside Windows folders. What kind of folder is and why it is needed you will find out below.

What is Prefetch?

Let's turn to the global knowledge repository - Wikipedia. It reads:

Prefetcher- operating room component Microsoft systems Windows speeding up the process bootstrap, and also reduces program launch time. Prefetcher first appeared in the operating room Windows system XP. Starting from Windows Vista, it was complemented by SuperFetch and ReadyBoost technologies.

It turns out that this system watches which programs you use most often and records them in special folder: C:\Windows\Prefetch

There are all sorts of different files stored there with strange extensions like this.

Well anyway Windows boot loader analyzing these records, it pre-drives the software into RAM to then speed up the response to your request.

By default, entries into the prefetch folder are made not only by system applications, but also by secondary applications, and this slows down loading. You need to make sure that only information from system files is written to the folder.

Using the hot combination Win+R, activate the command input window and enter regedit.

In the registry editor, look for the following branch:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SessionManager\Memory Management\PrefetchParameters

In the right window we need to change the parameter EnablePrefetcher.

RMB select “Change...”.

The default is three. “3” says that both system processes and various applications are running. If we set it to 2, then we will launch only system processes. If 1 means only applications, and 0 means disable them altogether.

Let's give it a two!

By pressing the “Ok” key we confirm the changes.

Let's sum it up

With these simple manipulations, we have optimized our Windows at least a little!

Folder Prefetch can be found in Windows XP, Vista, 7, 8 at the following path: C:\Windows\Prefetch - it is a component of the operating system and speeds up the process of booting the OS and frequently used programs. For the first time this technology was used in Windows XP, and starting from Vista it was supplemented with SuperFetch and ReadyBoost technologies. Launching an OS or application is accompanied by reading data from memory; often the same file has to be accessed several times, which is very irrational and takes a lot of time. Windows optimizes code loading by storing trace files in the Prefetch folder, which it processes in its own way.

To configure the Prefetcher folder, we need a registry editor. I would immediately like to duplicate the warning from the Microsoft website: “Incorrect use of the Registry Editor can lead to serious problems requiring reinstallation of the operating system. You use the Registry Editor at your own peril and risk.”

Click Start - Run and enter regedit. In the Registry Editor we will find the following section: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters

So that disable Prefetch you need to double click on the parameter EnablePrefetcher and in the dialog box specify the value 0 . The default is 3 - for more quick launch applications and Windows boot. The need to disable Prefetcher often arises when working with Windows 8 - many new laptops are not equipped with a traditional HDD hard drive, but an ultra-fast SSD drive, which are still characterized by high cost and small memory capacity.

At installed SSD Windows drive 8 should automatically disable the Prefetcher service, but if this does not happen, you can remove Prefetch yourself. In the above registry key for the settings EnablePrefetcher And EnableSuperfetch need to set value 0 , that is, turn them off. Restart your computer.

Windows system files and folders have many myths, and the service we are considering is no exception. We often hear questions: is it possible to delete the Prefetch folder, how to disable or enable Prefetch. But the most interesting misconception is that adding a key /prefetch:1 in the link to the object in the "shortcut" tab speeds up the loading of the application, since the OS, seeing given key, adds the program to the Prefetch folder. Adding /prefetch:1 to the address will do nothing, and the myth is based on the fact that a similar key is present in the line Windows startup Media Player.

People often ask, is it possible and necessary to delete files from the Prefetch folder? Supposedly, this allows you to free up space on your hard drive. The answer is clear: NO. Firstly, when these files are deleted, the loading time of the OS and some programs will increase, and the trace files will be created anew. Secondly, Prefetcher itself manages these files without the need for third-party intervention. In addition, Microsoft limited the number of trace files to 128 pieces so that they do not take up too much disk space.

In Windows XP the key /prefetch:1 by default it is added to the file address in the launch icon properties Windows Media Player. What is prefetch? The word prefetch is translated into Russian as “prefetch”.

The point of this feature is with Windows XP in general. It creates files in the prefetch folder containing information about the paths to these programs on the hard drive.

On sites in the top Yandex upon request "windows prefetch" You can find some misinformation about this feature in Windows XP. In particular, on the netler and izcity sites, the authors support the myths that to speed up the loading of programs you need to add address lines their shortcuts key /prefetch: 1 , and that to speed up system boot you need to periodically delete all pf format files from the folder prefetch.

On Windows XP Prefetch folder Usually located at C:\windows\prefetch. It contains Prefetch files with the extension *.pf - these are lists of files to download, so-called hash files. Their names are generated by hashing EXE files after downloading. Every time you launch EXE files, they are hashed and checked to see if there is a corresponding .pf files in the Prefetch folder, and if yes, then these files are downloaded. If no matching prefetch files exist, the system keeps track of which files it uses when launch EXE the program creates this .pf file and saves the paths to these files into it.

• So first of all, it's not very good idea- clean out the prefetch folder, as some computer sites suggest. The system will simply create all these files again, in any case, unless, of course, you figure out how to disable prefetch.
• Secondly, Windows automatically deletes prefetch files from this folder if there are more than 128 of them. Therefore, by clearing this folder, you will not only not speed up the loading of programs, but will also temporarily degrade the performance of your computer.

Next moment...

Some "specialists" began to add the /prefetch:1 key when starting programs. Many people have noticed that automatically created shortcuts for Win Media Player contain this key, and its meaning varies depending on the functions performed by the program. For example, the shortcut to a WMV file that you double-click to watch a video is assigned one prefetch key setting, and the autoplay shortcut for playing or ripping music that appears when you insert an audio CD is assigned another setting.

Some experts have suggested that the /prefetch: 1 switch enables the process prefetch. And they immediately began adding it to every executable file and recommending that others do it on various sites and forums. And thus this myth was formed. Other experts wrote on their sites that this is complete bullshit, and put forward the theory that this key is specific only to WM Player, having seen links to prefetch files in the Windows driver subsystem.

In general, neither one nor the other guessed right.

The operating system looks at the /prefetch:# parameter when it creates a process, and it does so for one single purpose. She adds serial number to hash. For what?

WMP has a lot different functions. The libraries and code it uses to play WMV are very different from the libraries involved in DVD playback, ripping a CD, listening to a Shoutcast stream, or any of the Windows Media Player features. If there was only one hash for WMP, then prefetch would only work correctly for one of its functions. When reading incorrect data from prefetch file there would be no fatal error - the .pf file would simply be loaded into memory and not be used. However, this would be counterproductive.

/prefetch:# option different numbers for each function Windows Media Player allows each function to create its own hash file, and thus the prefetching is done correctly. Such prefetch parameters are not unique to WMP. The same is done for any other application.

/prefetch option: is taken into account when the first thread in a process is created, but is not removed by the CreateProcess function from command line, so any application that doesn't accept unknown command line options will not work with it. That's why so many people noticed that, for example, Kazaa and many other programs produced errors or simply refused to start with windows prefetch. And WMPlayer, of course, knows that the key can be specified in the parameters, and simply silently ignores its existence.

All the /prefetch:# key does is change the hash number. The operating system loads a program with it in the same way as without it, simply storing the prefetch data in another.pf file.

In the process of studying Windows 7, 8, 10, or troubleshooting problems, you will be faced with the need to become familiar with the components and purpose of OS folders. In this material we will examine the following questions: Prefetch - what is this folder, can it be deleted, and where is it located.

Prefetch folder location and functions

Every time you turn on your computer, Windows tracks how your PC starts and what programs you open frequently. Windows stores this information as small files in the Prefetch folder. The next time you turn on your computer, the OS references these files to speed up the startup process.

The Prefetch folder is located in the OS directory, the full location looks like this:

C:\Windows\Prefetch. In your specific case The volume label may vary.

By going to the folder, you will see the ReadyBoot directory and files mainly with the pf extension. For example, OS loading is traced to a file called NTOSBOOT-B00DFAAD.pf. All other elements are traces of the launch of programs and service components. The files have a name in the name executable file, its hexadecimal hash path and extension, for example EXCEL.EXE-53A22446.pf.

The job of generating trace files is performed by the Prefetcher component, but without a functioning task scheduler, Prefetcher will not work correctly. Data received from Prefetcher is processed by the task scheduler and then written to the Prefetch folder.

It is also worth paying attention to the Layout.ini file. It is created every 3 days and stores data (a list of files and folders) that is used when starting the system and programs. Data from Layout.ini is used by the disk defragmentation utility to rationally arrange files on the hard drive.

Myths about deleting the contents of the Prefetch folder

It is often claimed that deleting the Prefetch folder results in faster loading times and more free memory. Some experts believe that Windows loads information from the Prefetch folder for all programs that have ever been run on the PC into , thereby filling it with unused data (this is false). These experts recommend deleting the contents of the Prefetch folder on a regular basis to save memory from unused data.

The Prefetch folder is self-maintaining; there is no need to delete or clear its contents. Windows maintains a certain number of entries in Prefetch and automatically cleans up unnecessary data, preventing the folder from growing in size. If you empty the contents of the folder manually, then Windows and programs will take longer to start the next time you turn on the computer. Deleted data will be recreated, resulting in long loading times. Deleting the Prefetch folder or its contents from the point of view of freeing up memory on the hard drive is pointless, since it weighs little. In our case it is about 40 MB.

Managing SuperFetch and Prefetch Components

By Windows default 7, 8, 10 automatically disables SuperFetch and Prefetch when it detects a system boot from an SSD. For SSD data technologies are of no value and completely slow down the launch processes with unnecessary operations. If the OS has not automatically disabled these components for the SSD, then read the instructions below.

SuperFetch is a service that predicts which applications you'll run next and preloads that data into memory. Windows allows the user to change settings or disable SuperFetch and Prefetch through the registry and OS services. If you are using a traditional HDD, then it is not recommended to disable these functions.

Important! To avoid mistakes, do backup copy registry or system restore point.

8.10. In the registry, go to the PrefetchParameters section (path at the bottom of the screenshot). Pay attention to the 2 parameters EnablePrefetcher, EnableSuperfetch.

Values ​​for EnablePrefetcher:

• 0 – shutdown;
• 1 - Enable to launch applications;
• 2 - Power on to start the system;
• 3 - Power on to launch applications and the system.

The default value is 3, change it to 0 or 1, 2. After changes, click OK.

Values ​​for EnableSuperfetch:

• 0 – shutdown;
• 1 - Enable for boot files;
• 2 - Enable for applications;
• 3 - Enable for boot files and applications.

Now you know what the Prefetch folder is, whether it can be deleted and which OS components manage it. It is better not to touch the contents of the folder, it maintains itself, there is no need for user participation. On HDD is better do not disable the SuperFetch and Prefetch functions, this will slow down the system as a whole.

Some users who like to rummage through system directories often come across the Prefetch directory. What is the folder in front of the user in in this case, not everyone knows. Let's try to fill the gaps in knowledge about what this directory is for and what data it contains.

Prefetch: what is this folder?

Let's start considering the issue with the submission theoretical material. At start operating system monitors the download process, saving all data about it to speed up subsequent launches in the Prefetch directory. What kind of folder is in front of us?

Essentially, on the computer’s hard drive, containing current data, parameters and components of the complete system boot cycle and launch of the most frequently used programs.

To avoid loading all the components from scratch next time, Windows uses the data saved on the hard drive. Some users, however, claim that for each subsequent system startup, the information stored in the Prefetch directory becomes outdated. Therefore, from their point of view, it is necessary to clean out the Prefetch directory from time to time. It’s a little clear what the Prefetch folder is. But not all cleaning enthusiasts know that the data in it is overwritten automatically after each start or launch of the application.

Let's look at the practical aspects of the issue of deleting its contents. A little later we will talk about how to disable the use of the loading acceleration function if this bothers someone too much.

Prefetch folder in Windows 7 and higher: is it worth emptying it?

Removing data from this directory does not make any critical changes to the operation of the system or installed programs will not cause.

But all those who claim that after removing information from this directory, loading the system and launching applications will become faster are absolutely wrong. Quite the contrary, because the system or program will have to re-launch its own modules, placing them in the operational or computer device, and this takes time. Using data from the Prefetch directory significantly reduces the time spent on these processes. Therefore, by and large, it is undesirable to do cleaning, much less delete the folder itself.

It is important to understand here that during subsequent downloads, data about the process will still be saved. So cleaning and removal will turn out to be what is commonly called “Sisyphean labor.”

Managing the contents of the Prefetch directory

If someone doesn't need this service, they can get rid of it. To do this you need to enter the editor system registry(regedit command in the “Run” menu, called by the combination Win + R).

Here you need to select the HKLM branch, and then through the system directory (SYSTEM) and the settings of the current control parameters (CurrentControlSet) go down to the memory inspection section, where the desired PrefetchParameters directory is located. It contains keys of the format 0x0000000z, where “z” can take four possible values:

• 0 - complete shutdown;
• 1 - acceleration of program launch only;
• 2 - optimization of Windows loading only;
• 3 - activation of the function in full (for both the system and applications).

The same settings can be made in the editor group policies or in the Computer Administration Tools.

It remains to add that the directory is located in system partition along the path Windows/Prefetch. I think it’s already clear what kind of folder it is and what it’s for. As a final piece of advice, it's best not to clear directory contents or change service settings that are set by default on the system.