Sorry to post another 3 vs 4GB RAM questions but this has me stumped (this is specific to the Core2 Duo)... I read (here) that the Core2 Duo chips can see up to 3.3GB with 2x2GB modules. I have a 2.16 (late 06). However trying to buy a matched pair online I'm being told 2x2GB modules may not work right in the 2.16, only the 2.2+. Huh? Won't what works in the 2.2 also work in the 2.16 only the 2.16 will show 3.3GB? The price difference is only $25. So why not get a matched pair and extra RAM? Is this a case of the sales guy won't go off the spec sheet? According to OWC that can increase the performance 50% during heavy loads (see the HOG test results)! Additionally the guy said my system USE to be on their sheet as able to use 2x2GB however they have since changed that. Huh? The guys at OWC usually know their stuff.