Adding a stick o' ram...speed or quantity?

Hello, I found a stick of ram laying around I forgot about and was thinking about adding it to my secondary PC. The mobo is a Soyo K7VE I believe and already has a stick of Kingston 512 DDR333 in it. The stick I found is a 256 DDR266. I know that adding the slower ram will lower ALL the ram to DDR266 but was wondering if the trade off in a slight speed decrease would be worth it for the 256 mb of ram increase?

The cpu is a Athlon XP 2000+mobile and the (mobo)fsb is 166. I mostly use the PC for Office, video/photo editing, and lastly gaming as it is my secondary PC.

depends on if you actually can use more memory than 512mb.

to be honest, using a divider like that with AthlonXP kills performance immensely. best to just stick with 512mb but test and see what suits your usage better.