C Windows Prefetch ReadyBoot ReadyBoot Etl: What It Is and How to Use It
If you are using Windows 10 on a solid state drive (SSD), you may have noticed a file called C:\Windows\Prefetch\ReadyBoot\ReadyBoot.etl that is constantly being written to. What is this file and why is it there? In this article, we will explain what ReadyBoot is, how it works, and how to optimize it for your SSD.
What is ReadyBoot?
ReadyBoot is a feature of Windows that aims to improve the boot time of your system by using data from previous boots to create a plan for a boot-time memory cache. This cache is used to preload files into RAM before they are needed by the system, reducing the disk access time and speeding up the boot process.
ReadyBoot is similar to the prefetcher feature of Windows XP, which also used data from previous boots to optimize the boot sequence. However, ReadyBoot is more advanced and can adapt to changes in your system configuration and usage patterns.
ReadyBoot works by recording the disk activity during the boot process in a file called ReadyBoot.etl, which is stored in the C:\Windows\Prefetch\ReadyBoot folder. This file is updated every time you boot your system, and it contains information about the files that are accessed during the boot process, such as their names, locations, sizes, and access times.
When you boot your system again, Windows uses the data from the ReadyBoot.etl file to create a memory cache of the files that are likely to be needed during the boot process. This cache is stored in RAM and released 90 seconds after booting up, or immediately if another service needs it.
How does ReadyBoot work with SSDs?
SSDs are much faster than traditional hard disk drives (HDDs), and they can access files almost instantly. Therefore, you may wonder if ReadyBoot is still useful for SSDs, or if it can actually harm their performance or lifespan.
The answer is that ReadyBoot can still provide some benefits for SSDs, but they are not as significant as for HDDs. SSDs still have some latency compared to RAM, and using ReadyBoot can reduce the number of disk accesses during the boot process. This can improve the boot time slightly, as well as reduce the wear and tear on the SSD.
However, ReadyBoot also has some drawbacks for SSDs. The ReadyBoot.etl file can grow up to 20 MB in size, and it is constantly being written to every time you boot your system. This can consume some disk space and write cycles on your SSD, which are limited resources. Moreover, ReadyBoot may not be able to keep up with the fast boot times of SSDs, and it may not be able to preload all the files that are needed before they are requested by the system.
How to optimize ReadyBoot for SSDs?
If you are using Windows 10 on an SSD, you may want to optimize ReadyBoot for your system. There are two main ways to do this: disabling ReadyBoot completely, or adjusting its maximum file size.
To disable ReadyBoot completely, you need to edit the registry settings of Windows. This is not recommended for inexperienced users, as it can cause system instability or damage if done incorrectly. You should also back up your registry before making any changes.
To disable ReadyBoot through the registry, follow these steps:
Open the Start menu and type regedit. Press Enter or click on the regedit app to launch the Registry Editor.
Navigate to the following key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\WMI\Autologger\ReadyBoot
In the right pane, double-click on the Start value and change its data from 1 to 0. This will disable ReadyBoot from starting automatically.
Close the Registry Editor and restart your system for the changes to take effect.
To adjust the maximum file size of ReadyBoot.etl, you need to use an elevated command prompt. This is a command prompt that has administrator privileges and can execute commands that affect the system settings.
To adjust the maximum file size of ReadyBoot.etl through an elevated command prompt, follow these steps:
Open the Start menu and type cmd. Right-click on the Command Prompt app and select Run as administrator.
Type the following command and press Enter: xbootmgr -trace boot -prepSystem -verboseReadyBoot. This will run a tool called xbootmgr that will prepare your system for ReadyBoot optimization.
Wait for the tool to finish its work. It may take several minutes and require several reboots. Do not interrupt or cancel the process.
When the tool is done, it will display a message saying The operation completed successfully. Close the command prompt window.
Navigate to the C:\Windows\Prefetch\ReadyBoot folder and check the size of the ReadyBoot.etl file. It should be smaller than before.
How to enable or disable Prefetch in Windows 10?
Prefetch is another feature of Windows that works together with ReadyBoot to optimize the boot process. Prefetch analyzes the files that are loaded during the boot process and creates a plan for loading them in the most efficient order. Prefetch also works for launching applications, by storing information about the files that are needed by each application in the C:\Windows\Prefetch folder.
Prefetch can be enabled or disabled in Windows 10 through the registry or the services manager. Here are the steps for each method:
Enable or disable Prefetch from the registry
Open the Run dialog box by pressing Windows + R keys.
Type regedit and press Enter to open the Registry Editor.
Navigate to the following key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters
Double-click on the EnablePrefetcher value in the right pane to open its DWORD value box.
To disable Prefetch, change its value data to 0. To enable Prefetch, change its value data to 1, 2, or 3, depending on your preference. Here are what these values mean:
0: Disable Prefetch for boot and application launch.
1: Enable Prefetch for application launch only.
2: Enable Prefetch for boot only.
3: Enable Prefetch for both boot and application launch (default and optimal).
Click OK to save the changes and close the Registry Editor.
Restart your system for the changes to take effect.
Enable or disable Prefetch from services
Open the Run dialog box by pressing Windows + R keys.
Type services.msc and press Enter to open the Services Manager.
Scroll down and find the SysMain service, which is responsible for ReadyBoot and Prefetch.
Double-click on it to open its Properties window.
To disable Prefetch, click on Stop to stop the service and change its Startup type to Disabled. To enable Prefetch, change its Startup type to Automatic and click on Start to start the service.
Click OK to save the changes and close the Services Manager.
Restart your system for the changes to take effect. 4aad9cdaf3