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Service Host SysMain : What is this service? Enable or Disable it?

service host SysMain

Service Host SysMain in Windows 10 Update 1809, Microsoft has chosen a new name for the SuperFetch service called SysMain. When we talk about “memory” in a computer, we are generally referring to the physical RAM that we have connected. Microsoft operating systems have additional features and capabilities such as paging file virtual memory or compressed memory (SysMain). Designed to maximize memory and keep your computer running smoothly, even under high workloads.

In Windows, in addition to using RAM, it has a known function as the paging file (virtual memory). Space reserved on the hard drive allowing memory loading and information storage. Thus, when there is not enough RAM, the programs that need memory refer to the paging file on the hard disk. With the arrival of Windows 10, Microsoft introduced a new feature to the operating system (which has been around for some time on Linux and macOS) called ” SysMain “. It is the best alternative to regular virtual memory in earlier versions of Windows 8, 7, XP.

Windows 10 Update 1809

What is Service Host SysMain in Windows 10?

SysMain is a feature that was first known in Windows Vista under a different name as SuperFetch. It sits quietly in the background, constantly analyzing RAM usage patterns and finding out which applications you run the most. With time passes, SysMain marks these applications as “frequently used” and preloads them into RAM. The idea is that when you want to launch an application, it will launch much faster because it is already loaded into memory.

As mentioned above, ” Host Service: SysMain ” is a new feature released with the release of Windows 10 that aims to be a swap file alternative, improving overall computer performance. Unlike the paging file (which can be enabled, resized, disabled, etc.), this option is enabled by default in Windows 10 and works without our intervention.

In early versions of Windows 10, SysMain was referred to as SuperFetch and was associated with the ” System ” process, which surprised me that this process was consuming large amounts of memory. With the Update Creators update, this setting is recorded in the Task Manager section as Memory Structure.

SysMain is the best option for a paging file, but this is not without a flaw, as the system will use the processor cycle all the time to access the compressed memory, which can slow down the computer.

Service Host SysMain

How does SysMain work in Windows 10?

By default, Service Host sysmain is designed to take up all available RAM space with preloaded applications. Don’t worry, this is just unused memory. As soon as your system requires more RAM (for example, to load an application that was not preloaded), it frees up the necessary memory as needed. 

Prior to Windows 8.1, if an application needs to use, for example, 5 GB of memory, and the computer has only 4 GB of RAM, then Windows was forced to send 1 GB of this data to the paging file, which is on the hard disk. Thanks to this virtual memory, it becomes possible to run and use this program, but it will run slower than with enough RAM.

Starting with Windows 10, when the operating system needs more memory than it has available, then the process of compressing data, like ZIP, into RAM, instead of sending it to the hard disk in a paging file, takes place. Thus, if we need to save two information data packages 6 GB and 3 GB and the computer has only 8 GB of RAM, then Windows 10 compresses the 3 GB package, reducing it to 1.5 and learns a total of 7.5 GB instead of 9 GB and can get to access it from RAM without resorting to exchange.

Service Host SysMain

Is it good or bad to have SysMain?

Windows will try to avoid using this method when there is available RAM, but when some data requires a large amount of memory when there is not enough RAM, the system will compress the data (squeeze) entering it into RAM to save resources, and try to force the computer to work well.

Most of the data is stored in RAM so that the system can access it directly and without problems. In virtual memory, or as the paging file is also called, data is saved to the hard disk, thereby reducing the time it takes for data to be transferred from the hard disk to RAM. Some users see that the memory is sometimes crammed with 3.5 GB, but this is not so scary when your hard drive at 100 percent can have a swap file. You just need to wait until the data is compressed into RAM.

If anyone wants to Enable or Disable ” Host Service: SysMain ” then look for the SysMain service in Device Manager. There is only one conclusion and it is obvious that compressed memory is much better than a paging file, which is even on an SSD disk.

disable SysMain

100 disk usage windows 10

  • Windows 10 disk occupancy rate of 100%

Some computers with Windows 8 or Windows 10 systems often have a disk occupancy rate of 100%, causing the system to be in a suspended animation state and nothing happens. So what is going on here? How to solve the problem of 100% high disk occupancy rate? The following MS Chief will share the solution to the 100% disk occupancy rate of Win10. You can alleviate the problem of high disk occupancy rate by trying the following settings or modifications:

  1. ) Reasonably set up Windows Defender scheduled scan

Windows Defender is built-in antivirus software for Win8 and Win10 systems, but the scheduled scan of Windows Defender cannot be turned off by default.

Then when Windows Defender is scanning, if you do other tasks, the disk usage can easily reach 100. %.

Although we cannot turn off the Windows Defender scheduled scan, we can set it to not affect our work, see ” Windows Defender scheduled scan settings tips ” for details.

enable superfetch

Or install third-party antivirus software to replace Windows Defender, such as free antivirus software “Dr.Web CureIt!” and “Avast!”.

Or simply disable Windows Defender directly.

2.) Close the family group

The “Homegroup” function will also increase the disk usage, so if you don’t use the ” Homegroup ” function, it is best to turn it off.

Three, close the IPv6 protocol

Win8.1 and Windows10 enable the IPv6 protocol by default, which will also increase the disk occupancy rate. At present, IPv6 addresses are not yet popular, so you can turn off the IPv6 protocol first ( how to turn off the IPv6 protocol in Win10 ).

tcp ip

  1. Turn off or optimize the “Index (Windows Search)” function

Update on August 12, 2018: With the feedback and assistance of Windows Insider preview members, Microsoft has discovered that one of the reasons for the high disk utilization of Windows 10 is the problem of Windows Search and solved the problem. The next Windows 10 version This problem has been eliminated.

Although it is widely rumored on the Internet that turning off “Index (Windows Search)” can improve the performance of the Windows 10 system, after the evaluation of authoritative IT media PC online, turning off “Index (Windows Search)” has limited improvement in system performance, and closing “Windows Search” will cause problems The well-integrated experience of smart search is lost in Win8 or Win10 system. So instead of shutting down the “Windows Search” service, it is better to optimize the “Index (Windows Search)” service.

windows search

Of course, if you insist on closing the “Index (Windows Search)”, you only need to close the Windows Search service in the Service Manager

Close SuperFetch (SysMain) super pre-reading service

Since Win10 1809, SuperFetch service has been renamed SysMain. SuperFetch (SysMain) super pre-reading service is mainly designed for enterprise applications and large-scale collaboration software, and individual users do not need to open it.

For professional software such as corporate strategy management used by large enterprises, the database startup process often takes as long as 10 minutes, and the use of SuperFetch (SysMain) super pre-reading service can reduce the startup time to less than 6 minutes. But for us individual users, the startup time of the software we usually use is very short, usually within 1-2 seconds, and the SuperFetch (SysMain) super pre-reading service is only 0.2-0.5 seconds or faster.

At this point, we can generally Ignore, and if the service is turned on, it will only increase the monitoring of the hard disk (loss of CPU performance time) and read time (increase the allocation of hard disk IO addressing threads). This is also the root cause of people complaining about the large hard disk usage. The SuperFetch (SysMain) super pre-reading service is also invalid for game programs. For individual users and game players, turning on the SuperFetch (SysMain) service will only invisibly lose CPU performance time and the thread performance of hard disk IO addressing..

Therefore, turning off the Service Host SuperFetch (Service Host SysMain) service by individual users will effectively reduce disk usage. The method of closing is also to open the service manager, stop the SuperFetch (SysMain) service, and set it to disable.

Set virtual memory reasonably

Although setting virtual memory can alleviate the lack of physical memory and improve system performance, it will increase the burden on the hard disk and cause the disk occupancy rate to increase. So if the physical memory you use is large enough, such as 4GB, 8GB or more, you can appropriately reduce the size of the virtual memory, but it is recommended not to be less than 2048MB, otherwise unknown problems may occur. For the method of setting virtual memory, please refer to ” Win10 Setting Virtual Memory Tutorial “.

Close the hard disk MS mode

Another reason is that when some SSD solid-state drives use StorAHCI.sys in AHCI mode, they may not be able to perform correct input and output operations under MSI, which shows that the disk occupancy rate is 100% and the system is stuck. If you want to solve this problem, the easiest and direct way is to disable MSI Mode in the registry.

  1. Turn off Windows Update or pause the update

Sometimes, when the disk utilization is shown as 100%, you can check in Task Manager and find that the disk utilization of the Windows Update process is the highest. As shown:

At this time, if you go to “Settings-Update and Security-Windows Update”, you will find that updates are usually being downloaded and installed. As shown:

windows update disable

Of course, for the safety and stability of the system, “Windows Update” is essential, so under normal circumstances, just wait for the completion of the Windows update, the disk utilization will drop.

If you are eager to work on the computer and want to update the time again, you can pause the update. the way is:

In the “Settings-Update and Security-Windows Update” interface above, click “Advanced Options”, and set “Pause Updates” to “On” in the “Advanced Options” settings interface that opens.

This can suspend the update for 7 days, but after resuming the update, if you want to pause again, you need to install the latest update first.

If you don’t want Windows update at all, or you have already suspended the update and cannot pause it again, then you can also open the service manager and stop or disable the Windows Update service directly.

Is SuperFetch/ SysMain going to slow down my computer?

We may wonder, this will possibly slow down the computer because Service Host SysMain consumes more resources. The truth is that no, except in certain cases. This service will only load the RAM memory that is free; it will not saturate the space that the system is using for other processes.

But there are also cases in which it does have a negative effect on our computer. In addition to using RAM, it will also consume CPU and hard disk. If we have a system installed on a mechanical hard drive and with a CPU that is not too fast, this service could sometimes cause a slow performance of our PC. The same happens with RAM memories below 4 GB; the preloading of applications at specific times of maximum load, such as the use of games or very heavy applications could give some lag in space management.

Another case similar to this is the use of RAM by Android. If we trust the RAM of mobile phones it is almost always very saturated, and it is precisely due to the large number of applications that the system preloads in this memory so that they are ready to be used when we need them. If we click on WhatsApp, surely not a second will pass until we have it open on the screen. This is precise because it is fully loaded into RAM.

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