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?
Solution:
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.
