Is Superfetch suppose to clean up after itself ? Solved

  1.    #1

    Is Superfetch suppose to clean up after itself ?

    After updating to FCU (1709) my startup time was slower and it appeared that Superfetch was the culprit. Superfetch was at 100% disk usage for a few mins, before it would finally calm down. Obviously, setting it's startup to manual or disabled eliminates this, but I was curious, so I went poking around and found the following.

    I took a look in the C:\Windows\Prefetch folder and noticed there were .pf files in there for programs and apps that I had uninstalled (before the update). So I deleted everything in the Prefetch folder (NOT the folder itself). After a couple of reboots my startup time was back to normal and Superfetch 100% disk usage would calm down much faster (less than a min).
      My ComputersSystem Spec

  2.    #2

    .pf files are regular prefetch files and not related to superfetch. When their number reaches some number (not sure what that is) the older ones will be automatically deleted. But it shouldn't matter anyway. Prefetch files for uninstalled programs will not be referenced and cause no harm.
      My ComputerSystem Spec

  3.    #3

    Hey LMiller7,
    I didn't think the two were related, until I manually cleaned up the \prefetch folder and it took superfetch 100% disk usage from a few mins to less than a min. Didn't seem like a coincidence, but maybe it was :)
      My ComputersSystem Spec

  4.    #4

    From what I can find, the number of .pf files is 128, but I had 275 ... So, either MS changed the number or it wasn't cleaning up after itself.
      My ComputersSystem Spec

  5.    #5

    Superfetch only runs once after logging in

    Some people say it takes 5 restarts to actually feel the improvements when Superfetch is enabled. I had Superfetch disabled in my laptop and everything is making it really hard for my hdd now I turned it on then did few restarts and I saw the significant difference
      My ComputerSystem Spec

  6. Geneo's Avatar
    Posts : 671
    Windows 10 Pro x64 Retail

    The prefetch files (.pf) are for preloading executables and drivers in a particular order for a faster boot time. If that is messed up it certainly could affect your boot time.

    You probably have prefetch enabled and it was corrupt, or non-optimal, probably as a result of the update. There is a registry setting that determines what is enabled (prefetch, prefetch + superfetch, etc.), can't recall what it is - you can google it. If you have an SSD, prefetch probably isn't that useful, but I think superfetch still is. You might as well disable prefetch in the registry with an SSD OS drive.

    Superfetch on the other hand, is for loading programs that you access frequently for faster access post login.
      My ComputerSystem Spec


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