A quick look shows that in 2002, we were using Pentium 4's and Athlon XP's, single core, around 1500-2000mhz.

Until I could afford to buy a PC, that's the class of hardware I used.

Just pick your favorite Linux distro, and they will run like new.

It's also worth noting that Arch Linux started in 2002. That's the distro I settled on back then (NixOS wasn't around yet ;).