Host OS: Linux Mint 21.2
Guest OS: Windows XP Pro SP3

I've found a lot of old 90's screensavers and installed them on my XP VM; about half of them work fine, but some go way too fast (probably syncing its framerate with the CPU instead of the clock), and some just make the screen black. Is there some setting in VirtualBox that can put a cap on the CPU speed or something like that? I've been struggling to install updates and drivers to my VM as well; not sure if that's related!

(I already tried posting on the VB forums, but when making an account it asked for my job title and income among other things, which smelled fishy to me.)

It's a shot in the dark, because I've never tinkered with it, but you might look in Settings-->System-->Acceleration.

Tried all the settings there, made no difference.

Sorry I couldn't help.

How much RAM did you give the VM? 128 MB was all that was required back in those days.

Really? My first computer ran WinXP and it had 2 gigs! I gave the VM 3 gigs for good measure. I'll try it with less.

Less RAM didn't have any noticeable effect, but I was able to slow it down with the "Execution Cap" option! However, that made everything laggy and inconsistent as well.

Win XP is 32 bit, and the speed of most apps at that time was controlled by the cpu clock cycles and not otherwise timed. Newer CPUs that run at GHz speeds process those commands at several orders of magnitude faster than originally planned. This means your VM is running on a CPU that is much faster than the CPUs that were available in the early 90s so of course things are operating much faster.

Newer software is actually timed by clock ticks and not CPU cycles.
I am not sure how the performance speeds could be controlled to be similar to what was available when win XP (and the apps used there) was created and in use. The first step might be to lock the VM to a specific CPU, then lock that CPU to minimum speed (some processors have minimum speeds of 800MHz or even less -- especially laptops). How either of those could be done is beyond my expertise.

I had an XP box, but I can't remember how much RAM it had. It was a long time ago . . . .

That's why I looked it up.

Again, I'm sorry I couldn't help. but computersavvy's suggestions look worth pursuing.

No apology needed! More info is still helpful~