Recently my Mac wouldn't boot up and I was receiving two beeps, which indicated bad memory. I bought some after market memory for my iMac (aluminum iMac) when it first came out two years ago. Not sure why it took two years to have a problem. I'm hoping the slot isn't bad. Right now I'm running with one stick and my Mac is definitely slower. I don't remember what type of memory to buy as it's been a while since I've given this any thought, and if you have a suggestion where to get it for a good price....I'd appreciate it. Thanks!