I'm looking to upgrade my 20" 2.0GHz and have been searching the internet for RAM and have a few questions: 1. I would like to upgrade to 4GB but someone told me the comp will only recognize 3GB. 2. Is there a difference between PC5300 and PC2-5300. I found 2 X 2GB sticks that I would like to buy but they are PC5300 and the comp. specificiations says it needs PC2-5300...whats the difference? 3. I will probably buy from OWC...any complaints?