I bought this in sept. of 08. The 24'' 2.8 ghz interl core 2 duo My mac came with 2gig 800 hmz DDR2 SDRAM. what are good places to upgrade to 4 gigs. I have $200 in amazon gift cards, so that seem to be the front running. Do I need a certain brand or will any brand work as long as its ddr2 sdram?