I've not known, Explorer to open instantly, or what I would call instantly, even on a fresh install, for some time IIRC. Heck, the amount of times I hit win+R to kick something off and that takes so long to open that the first couple of characters are missed and go to whatever window I had in focus at the time, is irritating. It certainly gets a lot worse when Explorer has been running a while (presumably this is why it has its own special case in Task Manager – pick Explorer and “end task” becomes “restart”) and its memory use has grown significantly (this is likely at least in part due to shell extension though the only one with any complexity I have installed here is MS's own TFS integration, and I have nothing like that running at home ATM).

Other things similarly take a while, like registering an update made elsewhere. These can be quite arbitrary, sometimes pretty instant, sometimes taking many seconds, and sometimes not updating at all until I explicitly refresh. I've even copied a small file to the same directory and waited several seconds before it showed up.

> Did you try to reinstall Windows?

For no sane desktop/similar operating system should “completely reinstall” be an off-hand answer for any but a massively significant error…

Try dissociating the photos app from jpgs. It triggers some strange CPU hogging and other side effects

Usually when the problem gets really bad, memory use has jumped into a few hundred MB. That seems to happen when I've switched between local login and acceding the machine via RDC.

Believe me, you simply do not remember how fast XP was. Install it in a VM and see for yourself.

I keep a bad memory of how slow XP, 2000 and even NT4 were on late 90s machines.

Windows 9x was a strange beast, being a VM running on top of a DOS hypervisor, but it was mostly C and inline assembly and felt fast, even with 8MB of memory and a 75MHz processor. Windows 2000 was quite less efficient and would have taken eight times the memory and twice the processor speed to achieve the same responsiveness. Even more with XP.

Nowadays Windows, the mere operating system, feels slow even on computers as powerful as datacenters of the 90s. Twenty five years of abstraction layers, subsystems, processes and libraries adding up, and it's getting worse (W11 vs W10).

Find some hardware from the time and compare. Certainly common hardware from around the time of the initial release. It might not run as fast as you remember.

It definitely won't run as fast as a VM on a modern host with a much more powerful CPU, significantly faster IO (especially if the VM is hosted on an SSD).

Also, once you hit the point where the guest OS can't cache as much as it wants (as you've allocated a realistic amount of RAM from time) the host layer may be caching reads at least in the extra memory it has.

[though I do get the point: if it can be as fast as it was on old kit, why can't Win10/Win11 be faster on modern kit]

Had this and several other persistent issues across reinstalls, across devices... in 2015 I remember when Windows 10 came out and it was full of absolutely ridiculous UI bugs, at the time people made fun of Microsoft for using the customers as beta testers. So I avoided it for several years, only to discover that they hadn't fixed hardly any of them...