What Is Superfetch (SysMain)? How could it Improve Performance?

What Is Superfetch (SysMain)?

Superfetch (SysMain) is a function that came since Windows Vista. The Superfetch service’s official description claims that it “maintains and enhances system performance over time,” yet it is ambiguous and doesn’t cover all the bases.

It silently monitors RAM consumption patterns in the background while learning the kind of apps you frequently use. These apps are “often utilised” over time, therefore Superfetch preloads them into RAM in advance.

Superfetch is set up by default to load all of the preloaded programmes into your RAM. Do not be concerned; it just affects unused memory. Your system releases the necessary amount of memory as soon as it requires extra RAM (for instance, to load an app that wasn’t preloaded).

The preloading memory manager, Prefetch, was first introduced in Windows XP; it should be noted that Superfetch is not the same as Prefetch. Actually, Prefetch’s successor is Superfetch. What makes a difference? Prefetch didn’t track usage trends over time and modify its preloading settings accordingly.

In the Windows Task Manager, “Service Host: SysMain” refers to Superfetch. The idea is that by having the app cached in memory, it will start much more quickly when you want to use it.

You may read more about Superfetch from the AVG website here :

Do We Really Need It?

In general, Superfetch is helpful. Superfetch probably performs so smoothly on a recent PC with good hardware or better that you don’t even notice it. It’s even possible that Superfetch is currently active on your PC without your knowledge.

However, Superfetch (SysMain) may experience the following “problems”:

  • When Windows 10 is installed on an SSD, the Superfetch performance improvements might not even be evident. You don’t require preloading because SSDs are so fast.
  • Since Superfetch is constantly working in the background, it consumes some CPU and RAM on its own.
  • The necessity to load programmes into RAM is still present even with superfetch. Instead, it moves the loading to an earlier period. Whenever that loading occurs, your computer still lags as if you hadn’t used Superfetch to launch the app.
  • Superfetch preloads a lot of data from your HDD to RAM, which might make system starting slow. Every time you start or restart your computer, Superfetch can be to blame if your HDD runs at 100% for a few minutes.

But the real question is, is it safe to turn off Superfetch on your system ? The response is Yes.

Choosing to turn it off has no negative implications. Keep your system working smoothly by leaving it on. But if your HDD or RAM consumption is high or your performance suffers when performing RAM-intensive tasks, consider turning it off and see if it helps. If it does, don’t turn it on. Alternatively, switch it back on.

How to Disable Superfetch (SysMain)?

Disable from the Services App

First, search for “services” using your Windows key or type “services.msc” from the Run prompt by pressing Windows key + R.

Then, look for “SysMain”, right-click on it and choose “Stop”. This will stop the Superfetch service.

stop superfetch or sysmain

However, once you restart your PC, the Superfetch service will automatically start again. To refrain this from happening, right-click SysMain again and choose properties.

Then, change the Startup type to “Disabled”.

disable Superfetch (SysMain)

Disable From the Registry

You can disable Superfetch from the registry as well using the Registry Editor. Playing around with the registry, though, could damage your Windows system if you make a mistake. So, it is best to backup your system by creating a restore point, you may follow the guide here :

To disable Superfetch by editing the registry, look up regedit in the Start menu search bar, then choose it from the list of results. You can also use Windows key + R to enter the Run window and type regedit, and then click OK.

In the Registry Editor, under “Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SysMain”, look for start under the name column. Then, right click it and hit modify.

Then, change the value data to from ‘2’ to ‘4’. Click “OK” to save changes and restart your computer. Your Superfetch service should stop running after your PC is restarted.

Disable Superfetch (SysMain) From the Command Prompt

You can disable Superfetch from the command prompt as well by typing several commands. Open up your command prompt by typing cmd under Start menu search bar or with the Run window Windows key + R. Remember to run it as “Administrator” as well.

Then, in the command prompt, simply type “sc stop “SysMain” to stop the Superfetch from running.

To totally disable it from running even after restarting your PC, simply run “sc config “SysMain” start=disabled“.


In conclusion, you won’t need to disable Superfetch at all if you do not see any speed degradation or if you believe that Windows is functioning normally. However, you may always try to disable it and see if it helps the performance of your PC if you believe that it is using too much CPU power or making your HDD to load slowly.

There are other ways to improve your PC performance as well. You may also try to clean up some disk space by following this guide here :

One thought on “What Is Superfetch (SysMain)? How could it Improve Performance?

Comments are closed.