How-To Geek

Increase the FileSystem Memory Cache Size in Vista

I’ve always wondered why Windows doesn’t allow you to set an arbitrary size for the filesystem cache. What if you have a slow hard drive in your laptop, but loads of available system memory? Shouldn’t you be able to maximize that memory in order to speed up hard drive access?

I’ve found a slightly documented tweak that will allow you to tell Windows to use more cache for the NTFS “pool”, which should increase performance if your system opens and closes a lot of files all the time like mine does.

According to the Microsoft documentation:

Increasing physical memory does not always increase the amount of paged pool memory available to NTFS. Setting memoryusage to 2 raises the limit of paged pool memory. This might improve performance if your system is opening and closing many files in the same file set and is not already using large amounts of system memory for other applications or for cache memory. If your computer is already using large amounts of system memory for other applications or for cache memory, increasing the limit of NTFS paged and non-paged pool memory reduces the available pool memory for other processes. This might reduce overall system performance.

I’ll be testing this change out myself, and I really hope to get feedback from our excellent readers on this one. Please note that I’ve not run any benchmarks yet, so I can’t confirm yet that this yields any major benefit in real-world performance.

Command Line Hack

Open up an Administrator mode command prompt by right-clicking and choosing Run as Administrator, or type in cmd into the start menu search box and use Ctrl+Shift+Enter.

Type in the following command to increase the cache setting:

fsutil behavior set memoryusage 2

To check the current value, type in this command:

fsutil behavior query memoryusage

To change the setting back to the default, use this command:

fsutil behavior set memoryusage 1


As always, these “slightly” documented settings can screw up your system, so perform at your own risk. Also, you’ll likely have to reboot the machine to see any difference.

Manual Registry Hack

You can also set this value by changing a registry parameter. Open up regedit.exe through the start menu search or run box, and then navigate down to the following key:



Double-click on the NtfsMemoryUsage key on the right-hand side and change the value to 2. Here’s the available values:

  • Not Set: 0
  • Set to Default: 1
  • Increase Cache: 2

According to the documentation the default setting is “1”, but by default the key is set to “0”. Typically in that scenario the setting of “0” means “Not Set”, which means the system uses the default setting. You should be able to change the value to either “0” or “1” in order to change this back to default.

This setting also works in Windows Server 2003.

Lowell Heddings, better known online as the How-To Geek, spends all his free time bringing you fresh geekery on a daily basis. You can follow him on if you'd like.

  • Published 02/19/08

Comments (26)

  1. pipo

    So, ideally, this should speed up the system if the system has a large amount of RAM. Taking into consideration all the other aspects stated above (like “… system is opening and closing many files in the same file set and is not already using large amounts of system memory for other applications or for cache memory…”), can 2GB of RAM for a laptop be considered “ideal” to make this tweak speed up the system?

  2. blink4blog

    Does this trick work for Windows XP SP2?

  3. ph15h

    Hmm. I have Vista Home Premium with 2GB of RAM. Maybe I should try this, but I don’t know the adverse effects.

  4. redswd

    Found this and just now finished rebooting after making changes. So far completely stable. Opened 8 apps in succession and all 8 opened a noticably faster. Thanks.

  5. Justin

    In regards to the fear of adverse system failures, remember that you can always F8 your system at boot-up and then choose to start the system under the last successful boot.

  6. Stephan Hodges

    Can you update this article with your findings?

  7. Paul Reiter

    I run Vista Home Premium, with 4 Gb of memory. Making the change to “2” did not seem to have any effect on my machine, so I changed it back to “1”.

  8. GeekToBe

    I change it to 2, then i tried pressing my documents back and forward.. i felt that its faster than when it was set at 0. Oh and i have 4GB ram.. Its good Its good!

  9. Matt Salas

    In checking my initial memory usage setting, I found it was set to “0”. I recently upgraded my Turion 1.8ghz Laptop from 1GB to 4GB, running Vista Home Premium (32-bit). I changed the setting to 2, restarted the machine. Wow! The apps in my systray populated almost instantaneously! I’ve been doing a lot of DVD ripping for archiving purposes. One Movie used to take as much as 1 1/2 hours previously. I just finished one in 38 minutes, and another in 40. What I suspect is that, having the memory usage set to “0” previously made taking advantage of a dual core proccessor, or the increased RAM, difficult, considering the usage was determined by the computer, based on the system environment and number of apps open. Perhaps, for what I use my machine for, this change has made it possible to take advantage of the hardware I have.

    P.S. It also dramatically improved the “smoothness”, and consistency of video I was streaming from my machine to a media center set up I have. No stutter any more, over a power-line sytem that I had been using with my previous settings. Try this, it’s a stable adjustment with NOTICEABLE improvements in an otherwise slow hoggish OS – Vista.

  10. Paul Reiter

    I tried this again, after Matt’s comments. Sorry, no big change again except that now I keep getting “low on memory” messages from Vista….and I have 4 gig of memory! It used to run about 50%, with this change more like 88%. The message must trigger at 90% or so.

    So I changed it back again to “1”.

  11. Teck

    Amazing! it really works very well with my vista.starting programs becomes faster! Thank you!!

  12. Lonnel

    I have a 1.37 gig ram and im currently getting vista lag alot less now than ever before. thanks for posting this!

  13. Michael Adams

    Setting is also valid for Windows 7. Will test to see how effective it is.

  14. Shah

    I have a computer with windows xp intel pentium 4 with 3.0ghz and 1gb ram and a laptop with 2.0ghz core 2 duo and 3gb ram. Will the benefits be noticable. I’m asking coz i’ve only seen 2gb and 4gb ram posts

  15. Barb

    Tried NTFSMemoryUsage to 2 in vistax64 with 8gb of ram Q9650 2.83GHZ cpu, Nvidia Gtx260oc Video noticed pictures opened much quicker plus have a pan and tilt camera which seemed to lag much less with this fix . Applications jump noticeably faster to the screen.

  16. abhinav

    hey i have a questn
    i have Hp dv-1006ax laptop with ati mobility 3450 HD 256 mb…………….will this method help in increasing the gaming performance of my laptop?

  17. Dave Earl

    I have some problem on installing the DVDRW on my laptop, when i try to run the software a message will appear ” You don’t have administrator rigth to process or no device detected”. but i have already run my vista as administrator but still same error will pop-up…so what to do?

  18. no

    dave right click and then run as admin or use reg hack for full user control.

  19. LayaRenee

    I just did this and restarted my laptop-I have vista-and pulled up several windows as well as tabs within windows. My laptop is so much faster now! Thank you!!!!!

  20. Samics

    I hav 2 Go of RAM,its seems faster now using MemoryUsage 2.
    thank u :)

  21. winterheat

    what about Windows 7, does this work too?

  22. winterheat

    It seems like this: before changing, going to Task Manager, and look at Cached Memory, then maximum usually is 1GB. But after changing this “fsutil behavior set memoryusage 2” then it can go up to 3GB (if I am recording video using an HD recorder box that has a lot of hard disk access)

  23. mkanet

    For me, the results were very obvious. I was a perfect candidate for this tweak. It’s apparent, not everyone get’s an obvious benefit from it. I have a Vista PC with a folder with over 30,000 images; and, a couple of other folders which contain several thousand folders and respective images within them. Browsing these folders either with Windows Explorer or a Media Center-type app accessing folders like that makes a night and day difference. I’m glad I found this tweak. So far, no side affects. General OS performance isn’t affected; just folder browsing and reading files from within those folders. I only have 4GBs of RAM on Vista32.

  24. thabo

    thank you

  25. burstingyourbubbles


    After doing all this testing and writing this article something was nagging at me. The Ntfsmemoryusage key exists in the registry by default and Microsoft lists the options for this key. Yet, making changes to this key made absolutely no difference. I thought, “I’ve got to be missing something.” I kept going over my notes. I can’t see where I’ve missed anything. I need some input. I’ve always said I’m no Windows expert, but I do follow the works of some folks who are. So I sent an email out to a couple of people who know way more about the guts of Windows than I ever will, people that I highly respect. I don’t know either of them but I thought I would give it a shot. The email contained a link to the unpublished version of this article.

    Only one of the two responded. Rafael Rivera of Here is his reply:
    “That registry value is only referenced in fsutil.exe. It is not referenced in any other system binary within Windows 7, meaning the value is purely there for compatibility reasons (otherwise does nothing). Increases in performance are purely imagined. You can quote me ;) ” Rafael Rivera”

  26. Gowtham

    what are the effects……..? im getting afraid to try it………! can smone tell me about it. friends. im using win7 professional, 2Gb….ram…

More Articles You Might Like

Enter Your Email Here to Get Access for Free:

Go check your email!