Registry Tweaks: How To Increase Or Decrease MFT Size

The MFT file – the Master File Table – can become quite large and for good reason. However, you can try tweaking it by increasing or decreasing the size of the reserved disk space of the MFT file. Recommended: Large MFT file = Better performance

Change MFT Disk Size

TIP: You should not try to decrease the MFT size, instead it is recommended to INCREASE the reserved disk space for the master file table to avoid defragmentation. If you have a large hard drive with a lot of disk space that should not be a problem. If not, then get one! If you are on a SSD, you might want to keep the reserved disk space low although.

Why Is The MFT File So Large?

The MFT file includes at the very least one entry for each file on your hard drive. As you can imagine you can easily have millions of files on your hard drive, even more on large drives. That’s why the MFT filesize is so big. The more programs you install, the more files you download the bigger the MFT file gets. That’s also the reason why Windows 7 reserves disk space for the MFT file. Makes sense right? We don’t want the MFT file to become defragmented and keep requesting more disk space as it grows. However, on a default Windows 7 installation the MFT file already reserves only very litte of the free space (12.5% by default). If you still want to decrease it, you can do that by deleting files or formatting your hard drive.

So, How Do I Increase The MFT Size?

Ok, now you want to increase it for performance reasons? You can easily increase the reserved disk space. Here’s how:

1. Step Open the registry

Open The Windows Registry

2. Step Uncollapse HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Control/Filesystem

Windows 7 Current Control Set Local Machine

3. Step Select Filesystem and then in the right pane double-click on the item NtfsMftZoneReservation

4. Step Change the value to 1 – 4 to change the reserved disk space of the MFT file:

  • Value 1: 12.5% of free space, default
  • Value 2: 25% of free space
  • Value 3: 37.5% of free space
  • Value 4: 50% of free space

Change MFT Size in Windows 7

By default, on my system Windows 7 used the value 0 for the NtfsMftZoneReservation.  The Microsoft documentation states that a value 1 – 4 is valid. If you are using the value 0 it is using the default value “1” – which means it is reserving 12,5% of disk space. Not a lot, so you can possibly speed up Windows 7 a bit by increasing the value.

Did this registry tweak work for you? Let us know!

Make sure to check out our category of tutorials for more useful Windows 7 registry tweaks! Below are some related posts:

Published: Thursday, March 10th, 2011 Last Modified: March 10, 2011

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