I swiped the 486 out a while ago for an eMachines Delhi III board. It has a 500MHz chip, that I can unfortunately only get up to 450 MHz. 200MB drive with ArcadeOS and Mame .98. Galaga doesn’t run full framerate (59/60 FPS) but with a frameskip of 1, it’s not noticable. Plus, I’m looking into another board that will support up to a 766MHz Celeron. With that I could run Namco Classics 1 & 2 with few issues.