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Why does Windows slow down over time?

I might be wrong, but I'm sensing a slight decrease in the speed of my system after about 6 months of running Windows XP. Most notably, games are a tad bit slower.

What is the definitive truth about this? I mean besides "Dude, M$ Windoze needs to be reinstalled once in a while, that's part of the cycle."

In my case: There are no more "resident" (so to speak) programs than on the day of installation. I did install/reinstall/uninstall a couple of dozen programs, could the Registry have been thrashed around? (Still, I'm not talking about slower start-up, but slower *operation* i.e. framerate and such.)

Is it the fragmentation? The pagefile is in one piece (not fragmented), besides I have a gig of RAM so swapping shouldn't be really happening. I defragged with the Windows utility, no change.

S&D Search & Destroy reports all is clean. I've used Firebird since day one, so no spyware.

I'm just curious about the theoretical explanation. Exactly which part of the system degrades over time?

Friday, June 18, 2004

"I did install/reinstall/uninstall a couple of dozen programs, could the Registry have been thrashed around?"

Guranteed.  But really, this is Windows rot.  It is STILL uncured.

Friday, June 18, 2004

Ok, but the question was pragmatic. What *is* Windows rot?

Friday, June 18, 2004

1) MS has a free download registry scanner/fixer program. It can clean up a lot of garbage. There's also a freeware thing called RegSeeker which does similar things.

2) Do a defrag every 6 months. Even if it says the percent of fragmentation is low. A few critical files your games may use frequently could be badly fragged.

3) Get both Ad-Aware and Spybot S&D and use them to clean out any spyware that came from Kazaa or BearShare and the like.

4) Run a virus checker at regularly scheduled intervals.

Friday, June 18, 2004

Aagh. Yeah I know what you mean. Windows just slows down and screws up gradually, unless you're super super careful about everything you install it just seems to gradually mire the computer down and the only way to speed it back up again is to reinstall. XP seems a bit better about this than, say, Windows 98, but it's still not ideal.

And I have no idea either. I suspect something to do with DLLs or something. Haha. The internals of windows are just such an ugly mess I don't think I'll ever be motivated to learn much about them. Hopefully when they release Longhorn they'll get the chance to throw most of the DLL Hell / messy backwards-compatible APIs out of the window, as mentioned in a recent Joel article. And I hope to god they nuke the fucking Registry too and store it in XML files or something, what a horrific mess. Give me /etc any day.

Friday, June 18, 2004

Then take your /etc and leave me alone!

Windows Registry
Friday, June 18, 2004

A few tips, although Windows slowing down is something we have to accept, for now.

- Run adaware, spybot search & destroy regularly. Once a month or so will do: you'll be amazed of what crap sneaks in when you're not looking.

- Run antivirus. Stay off the pig that's Norton, try something like Avast or kaspersky antivirus (both free for personal use)

- Get TweakXP (free evaluation works for 30 tries, plenty). There's a ton of little fiddles you can play to max out performance.

- Set pagefile to 1.5x amount of memory, both min and max must be the same to avoid resizing of the pagefile.

- Run windows defrag on your windows partition in SAFE mode (press F8 when windows boots). This helps defrag a lot of stuff that's normally in use.

- Use, as suggested above, RegCleaner or similar to clear out the registry for old and invalid entries.

- Install all security updates from, or get the latest Service Pack beta (build 2149) - it helps a bit + all kinds of security fixes.

- Keep all your manually installed applications in a separate partition - it's cleaner, and you know what to get rid off once you uninstall one (wtf is it with uninstallers - why don't they get rid of EVERYTHING they installed in the first place?)

Others may have additional notes - hope it helps.

A Pterodactylus Ate My Baby
Friday, June 18, 2004

I forgot to mention: Control Panel->Administrative Tools->Services. Disable any "started" services you don't need, like Fax Support, Remote Registry, etc. etc. Be a bit careful, though, and read the descriptions before you go berzerk.

A Pterodactylus Ate My Baby
Friday, June 18, 2004

It isn't so much that Windows slows down, it's that the continued dance of install/uninstall and writing data causes you to need to deframent hard disks and clean out the registry. What's worse is, of course, PC manufacturers ship us PCs chock full of crap, and no original Windows CD, so "paving" a box for most people is hardly any help at all, since it comes with 54,903 applications already installed.

Brad Wilson (
Friday, June 18, 2004

And another... :)

Turn off Indexing service for "fast file searches" rightclicking your drives. Especially your windows partition. How fast do you need to find etc/hosts anyway?

A Pterodactylus Ate My Baby
Friday, June 18, 2004

Huh, that's funny - I was wondering the same thing this morning.

Those are some good comments however, (the last 2).  Thanks,

Friday, June 18, 2004

Ok I'll shut up after this, (well so you hope):

If you got some wierd ghost installation CD of Windows XP with your 'puter, then you're a legal owner, and can download a fresh windows xp install off the net. I won't tell you where, but you got a legal registration code:

Jot down the key and install a fresh XP on your computer.

It's perfectly legal in MY country at least. If you're American, blindfold yourself and don't read this post, your laws may be dubious.

A Pterodactylus Ate My Baby
Friday, June 18, 2004

I can't believe that people are still recommending RegClean. What century was it again?;en-us;299958

"RegClean is not compatible with the products listed at the beginning of this article." [Office 2000, XP, 2003]

"The RegClean utility is no longer supported and has been removed from all Microsoft download sites."

And that was a long time ago. This article dates from 9/2003, and RegClean was last updated in 2002. Even then MS warned against using this tool on Windows 2000 or later IIRC.

Chris Nahr
Friday, June 18, 2004

I am well aware of how Windows historically suffered from 'Windows rot', but I haven't seen this sort of thing really happen since switching to XP and I've had some systems in daily development use for 2+ years now.  With XP, I find that as long as you keep the drive defragmented, things tend to stay pretty snappy.

If you are experiencing this sort of thing with XP and defragging hasn't helped, I'd definately suggest triple checking for adware programs using some of the tools listed above.  In my experience those are by far the biggest culprits when it comes to unexplained slowdowns on current systems and modern versions of Windows.

Mr Fancypants
Friday, June 18, 2004

Give Diskeeper a go, it is far better than the default Windows defragmenter.  With the added bonus of a "Set and forget" option, it'll sit in the background and check the HD when you're computer is idle and deframent if needed.

Mike Aldred
Friday, June 18, 2004

And, consider turning off system restore.....

Albert D. Kallal
Saturday, June 19, 2004

The biggesst reason your ocmputer seems slow is that you've gotten used to it.  When you first install Windows on your brand new 17GHz PentiumVIII with a terabyte of RAM, you say "wow this is awesomely fast".  After you've used it for a few months (or years), you learn to get used to the speed.  Now, it just seems too damn slow.

Another example: When you first go broadband, how fast did it seem?  How fast does it feel now?  Probably not as fast.  The actual speed of your broadband probably didn't change, you just got used to it.

It's amazing how much this affects things.  Human beings get used to anything.

Here's a good experiment:

- Think about what you feel is slow on your computer now.  Make a list of those tasks that seem slow.

- Measure how long it takes the computer to complete thos tasks with a stopwatch.  Repeat the test a couple of times (at least three).  Average the results.

- Defragment your hard drive.

- Re-run the tests with a stopwatch and record the values.  You now have an idea of how much faster defragging your hard drive makes the computer.

- Nuke your hard drive and do a complete reinstall of Windows and your applications.

- Re-run those tests on your fresh install.  You now know how fast your computer was when it was new.

- Compare the numbers.

Myron A. Semack
Saturday, June 19, 2004

You know, Myron, you might be on to something.

I got this brand new Microsoft keyboard and it "just doesn't feel the same, the old keyboard was so much better, etc etc." until one night I had to type a lot so I decided to pull out the old keyboard.

I was absolutely shocked. The *old* keyboard was *awful* now.

Saturday, June 19, 2004

Thanks all for the answers. I did deactivate a boatload of services, indexing and system restore, and defragged with O&O Complete/Name.

Booting does seem faster, but I didn't use a stopwatch.

Saturday, June 19, 2004

Don't get me wrong, your system may very well have slowed down.  There could be something going on that we don't know about.

All I'm syaing is that before you try fixing something, make sure it's really broken.

Without any real measurements, you have no way of knowing if your system really IS slower.

Myron A. Semack
Saturday, June 19, 2004

"The biggesst reason your ocmputer seems slow is that you've gotten used to it.  When you first install Windows on your brand new 17GHz PentiumVIII with a terabyte of RAM, you say "wow this is awesomely fast".  After you've used it for a few months (or years), you learn to get used to the speed.  Now, it just seems too damn slow."

That's not my experience at all.

Take a Windows machine and basically leave it alone (like, a server), and it persists at a constant level of performance.

Take a Windows machine and use it regularly (install, uninstall, move data around) and it degrades. Take the same machine and pave it, and it's fast again, until it degrades from regular use.

Brad Wilson (
Saturday, June 19, 2004

And how have you measured this?  Do you have some timing numbers with a stopwatch?  Do you have some benchamrks with WinStone or Sandra?

How do you really KNOW that it's slower?

Myron A. Semack
Sunday, June 20, 2004


are you suggesting repaving is just a placebo?

Just me (Sir to you)
Monday, June 21, 2004

It's a possibility.  I'm not ruling out that Windows could indeed be slowing down.

However, no one has been able to say "IE used to take 5.4 seconds to launch, and now it takes 11.7 seconds."  Instead, the topic starter said "I'm sensing a slight decrease in the speed of my system" and that "games are a tad bit slower".

Without measureing it, how do you know if it is or isn't a placebo effect?  Is it really slower?  If it is slower, by how much?

I'm genuinely curious.  We've all heard about how Windows degrades over time, but I know I've never measured it, and I've never heard of anyone else mesuring it.

Myron A. Semack
Monday, June 21, 2004

On the NTFS files systems, a large percentage is reserved for indexing, an area called the MFT.  Once the hard drive heads near full, the file system will automatically shrink the MFT reserve to make some extra room.  On a heavily fragmented drive, this could come as early as 30% remaining hard drive capacity.  Once the MFT shrinks, it won't grow again until you re-format.  And once it gets too small, hard drive performance degrades rapidly.

Here's some info:;en-us;Q174619

Ben Allison
Monday, June 21, 2004

Interesting link.  I had no idea that it did that.

Myron A. Semack
Monday, June 21, 2004

Despite all that's been said, Myron's first post is the most acurate one for me. After playing with my computer for 2 years, I recently formated the hdd and reinstalled windows xp, and, lo and behold, it still felt sluggish. Of course the machine was the same, only my perception of it had changed.

Tuesday, June 22, 2004

I have a four year old installation of W2K on my desktop and it is just as fast as the first day, except when booting, which can take up to five minutes and two tries!

On the other hand the work desktop can be real slow, though this may be the network.

The registry is the probable culprit of the behaviour mentioned by the OP. 

Stephen Jones
Tuesday, June 22, 2004

"The registry is the probable culprit of the behaviour mentioned by the OP.  "

Could you explain that in a little more detail?

Myron A. Semack
Tuesday, June 22, 2004

It just gets larger and larger as you install and uninstall apps.

Moreover, you often find it's not been cleaned up properly, and tries to load files that don't exist.

I'm guessing this by elimination though. The only factor for a real slowdown is the registry since defrag tends to solve the other possible culprit.

File corruption is another possibility, though I would have thought that would stop the program, or even the OS, loading.

Stephen Jones
Wednesday, June 23, 2004

I can see the point about the registry trying to reference files that doen't exist, but that would cause "file not found" errors, not Windows slowdowns.

However, I don't see how the registry "filling up" would make Windows slow down.  So what if it gets bigger?  How does that hurt anything?

RAM utilization can't be an issue.  Infrequently accessed parts of the registry will get flushed to to pagefile.

Disk fragmentation COULD be an issue, but the registry gets defragged when you defrag your hard disk.

The registry is a transactional database.  Do queries on the database get slower as more records are added?  I immagine that at some point they would, but it would have to be a LOT of records.  After all, even Access can handle many thousands of records without choking.

Do you have some evidence to support your statement that registry growth makes Windows slower?  Do you have some benchmark that can show how many transactions/sec the registry can handle?  Can you show me how that number decreases as the registry grows in size?

You made that claim, surely you have some evidence to support it.

Myron A. Semack
Wednesday, June 23, 2004

Over time, you will accumulate errors during hard disk reads and writes. (It's a statistical fact.) If I recall correctly, Microsoft set a threshhold for the number of errors it would tolerate before renegotiating its IDE drivers. You go from ATA133 to 100 and so forth. I think it might even go below ATA 33 into the PIO modes. Anyway, the simplest resolution to this is to go to your system hardware, and remove your IDE controller. Windows will reinstall the drivers upon a reboot and should perform the same as it did before. (Assuming your files aren't fragmented, your registry isn't a mess, etc...)

Tuesday, August 17, 2004

I have heard rumors of a dynamic hdd optimization system.  Over time, windows moves data around on the harddisk based on how often it is accessed.  This sounds like a terribly encumbersome and sensative mechanism.  If this does exist, it's my first assumption as to the cause of this phenomenon--
another unnecessary feature making our lives more difficult. 

Thursday, September 2, 2004

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