I have always heard that it's a bad idea to install lots of software on a Windows machine, and new software should always be tested in a virtual machine so as to not permanently affect the operating system. But does the actual act of installing a piece of software really slow down the Windows OS? Or is it more due to the programs themselves running a bunch of background services?

To rephrase my question, if I were to continuously install software but then remove it later, would Windows still slow down?

4 Answers 4


If you're installing, trying and uninstalling lots of software, then a VM is very useful because they can be quickly reset to allow testing of new software in a "clean" environment - so there are other advantages.

As for your question:
Possibly. It depends entirely on the software.

If a piece of software uses/installs services, registry entries, background tasks, drivers, shared DLLs, etc - then yes you could potentially get performance loss. Even more so if it doesn't remove them when you uninstall the software.

But, any well written software should entirely clean up after itself when uninstalled.

Bottom Line

If the software isn't running and doesn't install any services, registry entries, background tasks, drivers, shared DLLs, etc, it will only reduce your disk space and not affect your performance (unless you're out of disk space, but then you've wider issues).

If the software installs any services, registry entries, background tasks, drivers, shared DLLs, etc (and/or leaves it behind when uninstalled), you might get performance loss. But it also might not be noticable until you've done this with lots of software, depending on how powerful your system is.

  • 1
    So then, any performance hit is the fault of the software developers and not Microsoft. What do you mean by "system core", though? Aug 25, 2010 at 9:53
  • 2
    @music Sorry, "system core" was me being lazy and not retyping "services, registry entries, background tasks, drivers, shared DLLs, etc" from earlier in the post. And yes, I'm inclined to say fault is primarily with the software, not Mircosoft. In theory if you install then uninstall a piece of software the system should be identical to how it was before the install, this is unfortunatly often not the case.
    – DMA57361
    Aug 25, 2010 at 10:02
  • I see, so my suspicions were correct, then. Great answer, and thank you very much. :) Aug 25, 2010 at 19:36
  • "Registry entries" in general don't slow down the system any more than files do. Really, the registry is just a file system for very small files. Jan 6, 2019 at 23:35

In practice the answer is a bold Yes.

With so many developers of all kinds, so many automated tools to generate the installation files, installing and loading the libraries, etc etc etc, and most important, the absolute lack of a culture of respecting the machine's owner's decisions above everything else when developing software (perhaps due to the Operating System itself being designed for users who don't want to take such decisions in first place, plus the fact that there is in general no open source so that people could look in it and say "hey, com'on, you'r installing useless s%#t to my system core", etc) lead to a de facto consequence which is this bold yes.

In theory there may be Windows software that can be installed, uninstalled, and leave absolutely no change in it. We could even try to make a list of such. I assure you they are insignificantly few.

One could indeed possibly say, though, that it's not directly MS's fault. It's arguable.

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    Yes, it likely has very much to do with the culture behind Windows. I never see this kind of stuff going on with Mac OS X or Linux operating systems. Aug 25, 2010 at 19:47

DMA57361's answer is perfectly valid but an alternative approach would be to use a SandBox:


This gives you the option of trying out programs on your computer without a virtual machine and having them run in their own little... sandbox...

I'm not making a recommendation of this tool based on the fact that I've used it, just that I have heard about it, there may be better alternatives available that implement the same "sandboxing" concept.

  • Yes, I am actually using Sandboxie, but it doesn't work with a lot of programs, so I am forced to install them natively. I was just wondering if that will eventually slow down my system. Aug 25, 2010 at 19:35
  • That's a shame, it looked like a nice tool and a lot less hassle than using a Virtual PC. Aug 26, 2010 at 5:47
  • Yes, it's a great tool for use with fairly simple software, but pretty much anything that does any low-level system trickery (like DRM) will likely not work. For me, it failed when trying to install pretty much any non-trivial commercial program. Aug 26, 2010 at 8:51
  • A VM seems to be as a much better solution.
    – Chris
    Sep 6, 2010 at 15:05
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    A hassle? Effortless to install, effortless to replace. Resource hog? 6gb vm will run 2-3 VMs just fine along with host.
    – Chris
    Nov 7, 2010 at 11:50

This is true that after installing lot of softwares the performance goes down. But we can increase performance also. Windows provides a functionality called Startup management. We can start programs which we require on startup. so speed up can be taken. goto to RUN type "msconfig"

then click on last tab startup.

then you can checklist which programs to be start at login.

  • But then it's not the installation of the programs that slows Windows down, it's the programs themselves, and that was my question. I know how to turn off services and remove programs from the startup list, I was just wondering if there was more to the slowdown than that. Thanks for the answer though. Aug 26, 2010 at 8:52

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