I've got a couple of Socket 754 based PCs, 1 with an Athlon 64 3200+ & the other with a Sempron 3000+. I built them back in the day as cheap HTPCs, 1 of which was used until around 2015 with a Radeon HD 3450 512MB AGP Graphics card, capable of decoding H.264 @ 1080p HD.
I pretty much haven't touched these PCs since they were retired. The specs are kind of inbetween my current retro gaming builds, with a Socket A & Socket 478 covering early-mid 2000s and Socket 775 Core 2 covering mid-late 2000s. As such, I've never really considered repurposing them as Gaming PCs. With the right graphics card, they'd probably make a nice build covering early-mid 2000s games with Windows XP and have the bonus of running a lot cooler than the Pentium 4 & less power hungry than the Athlon XP. Performance wise, the top end would probably compete well against a non-HT Pentium 4 and would also be better than the Socket A Athlon XP.
I never had a Socket 939 build, I skipped straight to AM2.
I also have a laptop with a Turion 64 MK-36 2.0GHz, but this was given to me for free and hasn't seen any use in a couple of years, plus also has a dead battery. If I ever decide to do a Gaming Laptop setup, this would probably be a contender as it has Radeon Xpress 1100 Graphics and could probably handle late 90s to early 2000s stuff. The current installed OS would definitely have to go, the poor thing was upgraded to Windows 10. 🤣