Is It Safe to Disable SysMain?


Superfetch, now renamed as SysMain, is a windows service that claims to fetch your frequently accessed files from the hard disk and preloads them in your RAM for quicker access. On paper, this sounds like a useful service. But in reality, this is still a poorly functioning double-edged sword—since XP.

In daily usage, most of the times, the service keeps the disk usage at 100% for prolonged times, causing issues like lagging, stuttering, and sometimes temporary input freezes.

This Geekswipe helper article is intended to be a guide to help you decide if you should disable the Superfetch aka SysMain service.

Should you turn off SysMain?

Though it is completely safe to disable Superfetch, you wouldn’t need to do that on modern computers. The reason is more complex than it would seem.

A system optimization service like SysMain utilizes machine learning algorithms that train on parameters that vary with every user. So what may work for an average user might not work for a power user, and vice versa. Windows, being marketed for an average consumer, sure would have their housekeeping services optimized for a regular user.

Superfetch or SysMain works by learning the RAM usage patterns and ‘predicting’ what files to proactively load and when to do that. This is how it is supposed to be anyway. As with Microsoft’s take on Windows housekeeping, it’s always a half-baked hit or miss implementation. Which simply translates to SysMain is unpredictable most of the times.

And I say this from my observation since the Prefetch times in XP. Sometimes SysMain does improve performance, mostly in the long run, but most of the time its I/O takes a high priority despite any low priority setting and randomly locks up the system when a high priority application requires the disk.

In my past, almost all of my simulations, games, and video editing crashes are entirely due to the Superfetch service spawning up at crucial times and claiming the disk for itself.

This usually happens when the running programs would need the RAM space and Superfetch has to release the irrelevant preloaded files off to the disk. So yeah! Unused RAM space is good at times like this.

So it is up to you. Disabling it won’t cause any serious issues whatsoever. You would notice a few frequently used applications booting up slowly and would have some free RAM space, and that is all to it.

If your productivity is hindered by SysMain taking up all the memory, just disable it by following the steps below. Do not listen to any Microsoft fanboys who claim you shouldn’t touch Superfetch nor you should ever disable it. It’s safe. You can.

Is it safe to disable SysMain on an SSD?

With SSDs you get a superior performance compared to mechanical drives. And in this case—when SSD is your only storage—it doesn’t really make a difference if you enable or disable Superfetch, as the service stops itself. But make sure it is turned off. Because an active SysMain will readily degrade your SSD with repeated I/O.

If you have a mechanical drive along with an SSD, you’d still have SysMain service running. At best, you wouldn’t notice the disk usage spikes caused by the service. At worst, the freezes or lags from the usage won’t last long enough for you to notice on the SSD.

Steps to disable SysMain on windows 10

  • Search for services in the windows search (yeah, the same ridiculous start menu search that will probably show web results instead of system results).
  • Find SysMain and go to properties from the right-click context menu.
  • Change the Startup type to Disabled.
  • And finally, in the Service status section, click on Stop and kill it.

This post was first published on September 7, 2012.


Karthikeyan KC

Aeronautical engineer, dev, science fiction author, gamer, and an explorer. I am the creator of Geekswipe. I love writing about physics, aerospace, astronomy, and python. I created Swyde. Currently working on Arclind Mindspace.

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1 Response

  1. Great Karthik.. Thanks :)