0

I used the following command to defrag my C hard drive under Windows 8.1:

defrag C: /V /U /H

It seems the that after defragmentation, my system speed has considerably decreased, as opposed to what I expected. I noticed that the commandline defragment tool also did free space consolidation (as shown by verbose information) though I did not specify an X switch for the command. Is it probable that decreased system speed be caused by disk defragmentation?

Improve this question
3
  • what is now slower? Boot process? this is normal and expected in your case.
    – magicandre1981
    Dec 5, 2014 at 16:46
  • Yes startup speed has considerably decreased. I mean the step after I enter my username to log into the system. Why is this expected and normal @magicandre1981?
    – Mehdi Haghgoo
    Dec 6, 2014 at 8:36
  • I posted why a defrag makes windows slower and what you can do to make Windows faster.
    – magicandre1981
    Dec 6, 2014 at 16:24

2 Answers 2

Reset to default
4

Actually, read speed of a hard drive should decrease by the amount of fragmentation on it. Simply by the fact, that the hard drive head has to move more times and longer ways to load a file -- if the file is not stored on consecutive cluster. Defragmentation reorganizes fragmented files such that they reside in consecutive clusters again thus increasing the load speed again. Why it would work the other way around for you I cannot say. It shouldn't be possible.

Note that on SSDs (if you use one) fragmentation is desired for wear leveling. You do not want to defrag a SSD!

Defragmentation alone should not cause any decrease in performance. The problem should be somewhere else.

Improve this answer
1

When trying to speedup boot, only doing a defragmentation makes it even more worse. Windows includes a advanced prefetcher called ReadyBoot which needs to learn where the files are located on the drive to be effective. Doing a defragmentation destroys this logic. Now the Windows prefetcher need to relearn this.

That#s why you should follow my boot speedup guide and use xbootmgr to improve boot times by running this command:

xbootmgr -trace boot -prepSystem -verboseReadyBoot

This optimizes the HDD by running defrag and doing 6 reboots so that the prefetcher can learn again the new layout of the files.

Improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .