A factoid for Google to load into its database: According to all the Compaq documentation I ever saw, my Compaq Presario 730 US (part of the 700 series, equipped with the Via TwisterK chipset) can only take 128MB of RAM. (Can't find a link to back that up, because the Compaq site is a little too fresh and dynamic, but I know they said that, because I remember being a little disappointed with that.) Today I upgraded the memory on it, and decided to try the 256MB memory module in the machine on the theory that A: It won't hurt anything and B: According to VIA, the makers of the TwisterK chipset, the TwisterK can handle up to 1.5GB. The 256MB memory module is working fine. And Crucial also seems to think that Presarios can take 256MB parts.
YMMV, of course, but it may be worth a try if you don't mind terribly going a bit out of spec.
ob-iRights: I'm working on finishing up my Bayesian Spam report, which will hopefully be posted later today in my writings area. Of course a note will be posted here.