Added memory to powerpc G4 - not working /whats up?

[Emergint]

Hello,
my computer is a 733 MHZ Power pc G4 with 3 ram slots, each taking 512mb - 2 of them were full so i bought one more - Through crucial.com - it was going to cost around $60 so i went the ebay route and got one for $11. What a deal! Only problem, is that it doesn't work. It fits in the slot fine but my computer is not showing the extra memory at all. i tried switching the new RAM with one of the old ones and when i restarted, i just heard 3 loud beeps and the screen never lit up. So what s the problem - Obviously i have the wrong kind but what do i need to look for to make sure i get the right kind next time?

The info on the ram is 512M PC-133
The older ones have a little more info (the are from different companies) They both say PC 133CL3 and one has a Patriot sticker.

Any help appreciated!
Thanks!

[Turboladdade]

A simple rule is to always buy Memory at OWC, who is Mac-centric, always reliable and quite cheap.

[Emergint]

Thanks, I'll check it out