512 or 758

i have one stick of good pc3200 cas 2 with 512 and one crappy OC system pc3200 at cas 2.5. would it be worth it to use both. i'm getting a 2100 tbred b and i plan to get the fsb over 170. I would really like to help my father out he only has 256. and i would give my 256 if it really didn't help me.

Don't bother with the 2nd stick. It'll slow down the system due to bank switching and the general crappiness of the 256 stick. And there is no appreciable gain in any (that I know) of todays apps to justify 768 or 1GB other than bragging rights.