Adding RAM to 2007 Macbook

Hi, I have a 2007 Macbook with the Intel Core 2 Duo processor, 2.2 GHz, that currently has only 1GB of RAM. I would like to add as much RAM as the processor will recognize and upgrade to the new OS. How can I determine how much RAM my system can utilize? Many thanks!
Mary Anne

Apple says you can put 4 GB in that machine, Mactracker says 6 GB. Personally, I would just put 4 GB. That means you need to remove the two 512MB modules and replace them with two 2GB modules.

Your machine uses: 2 - 200-pin PC2-5300 (667MHz) DDR2 SO-DIMM

Which you can buy either from Crucial or OWC. I prefer OWC.

Great, many thanks.

Does OWC ship to Canada and if not, where is the most recommened site to order ram for macs in Canada ?

P.S. Would a 1GB ram upgrade in a 2007 macbook(black one) make much of a difference for a light casual user ?

You can just run a scan on crucial.com and they will tell you exactly!