Gaming RAM 3/4 GM early 2007 MBP

I would like to know if I can run this game, FIFA 12 says it needs 4 GB of RAM, my machine apparently has a capacity of 3 GMB (currently 2)
link below states that only 3 GB out of 4 GB would be used at once... can I run that game if I upgrade my RAM? Mine is an early 2007 (Feb) MBP 15 inch-http://www.appleserialnumberinfo.com/Desktop/index.php

Why are the MacBook Pro "Core 2 Duo" models limited to 3 GB of memory? If I install dual 2 GB modules, why won't I be able to use 4 GB of RAM? @ EveryMac.com

The link you provided explains it very well. Even though you may install 4 GB of memory, the machine will only use 3 GB because of memory overlap due to the way the Intel 945 chipset is designed. So no, you probably can not run that game.