After applying all the updates, it was almost uselessly slow until I disabled the Spectre and Meltdown patches (not best security practice, I know), but now it's only a little slow, particularly at starting up and launching programs I attribute that mostly to the fact that it's installed on a spinning hard disk, though, so I can live with it (SSDs are so much faster!) It turns out that 7 actually does what I want better, if only by virtue of the fact that it can support newer, bug-fixed versions of the programs I wanted to use.

Recently, I did break down and install 7 on the same computer, so now I have both. Most importantly, I was able to preserve the OEM activation, so it behaves just as the untouched CD would, which is good because activating an OEM copy for which I don't have a product key is a pain. NET and WMP updates wouldn't slipstream (nor would WMP11 itself), so I had to install those by hand after installing, which was mildly annoying, but far better than what would've been had I not made the updated installer, since it was maybe like 12 or 15 updates instead of 200+). I followed the instructions at the RyanVM forums, added the latest 2019 post-EOS updates, and slipstreamed most of the whole thing into an OEM Dell XP 圆4 CD, and it works! (a handful of. OK, forgot to update here that I managed to succeed!

Windows xp service pack 3