Service Host SysMain, previously known asSuperfetch, is a caching service that preloads boot files and commonly used programs into the RAM to improve load times.
SysMain is supposed to improve system performance, and normally it does. But ironically enough, it can sometimes malfunction and worsen performance via high disk, memory, and CPU usage.
In the article below, we’ve detailed the reasons for this and how to resolve the SysMain / Superfetch High Disk Usage issue.
What is Service Host SysMain (Superfetch)
As stated, SysMain is a Windows feature that attempts to reduce load times. The way it does this is by analyzing application usage patterns and timing.
For instance, let’s say you power up your laptop in the morning and usually launch Chrome, Outlook, Spotify, and Discord. Over time, SysMain not only learns what programs you run most often but also the timing and order. Using this info, it preloads the applications into the Standby Memory.
Standby Memory contains cached data that isn’t actively in use. You may be worried that background programs are occupying the memory and affecting system performance. But this is not the case. As this memory is marked at low priority, if the memory is required for something else, it will be given up.
To sum it up, Service Host SysMain preloads frequently used programs into cached memory without affecting system performance. At least, when it’s working as intended anyway.
Why is SysMain Using So Much Disk CPU Memory
When analyzing program usage patterns, SysMain will sometimes overdo it and overtax the HDD. In some cases, the PC basically becomes unusable for the first 10-15 minutes after booting because it attempts to load too many programs at once.
Other reasons for high resource usage include running an application with faulty backend code, asaddressed by Microsoft, or attempting to preload very large files (AAA game files, for instance).
How to Fix Service Host SysMain High Disk Usage
Ideally, you could upgrade your RAM or switch to an SSD to resolve this issue. But we realize this advice isn’t very practical. Instead, we recommend that you turn off the SysMain service.
Disable SysMain from Services
For most users, disabling SysMain via the Services utility will be most intuitive; so here are the steps to do so:
