I have an aluminium 2007 iMac. It originally had 2GB RAM, 1GB in each slot. I upped the RAM a couple of years ago, replacing one slot with a 2GB RAM card. A couple of months ago, I was trying to install a piece of software and I got the message telling me I needed a newer OS than Snow Leopard. I found the free Mavericks upgrade and went ahead. Bad move. My mac is now running like a turd. Apparently 3GB isn't really ideal to be running Mavericks on. A friend of mine who works in a PC shop out of town has got me a 2GB RAM card so I can replace the 1GB slot and take it up to an overall 4GB. I'd been on the Crucial site, scanned my system and taken a screen shot of the card I need. He's got me a card, but says it's a generic DDR2 5300 card, laptop size (not tower size) to fit the iMac. Will this work ok on my machine or does it need to be Mac specific? Thanks.