Well, if it's very light gaming and just general use, including folding, I would stick with 128MB at 133MHz. That should be enough to handle those uses and the extra memory bandwidth is hard to do without.
It may slow down a little if you try to play more recent and very graphic intensive games, but older ones should present very little problem. Afterall, most games are still geared to be compatible with that much memory and type PC. Doesn't mean you'll get blazing FPS but it will be playable.
well jon what usually gets played on this computer is age of empires II, red alert 2 yuri's revenge, and i play ut...i struggle at 17-18 fps with everything turned to low and at 800x600...but with more ram in it is at 20 fps...sad i know...also with the additional ram in it still says that i only have 50mb of ram free at almost idle so i dont know what is up there