I've got a rather useless old iMac with the 1.83 GHz processor and the factory-installed 512 MB 667 MHz DDR2 SDRAM sitting in my house. I wanted to take it to school with me, but I figured I'd try to "trick it out" before I left so that it wasn't pathetically slow. I have 2 GB (4 x 512 MB) of DDR2 667 MHz SDRAM from my Late 2007 MacBook that I replaced a couple of years ago and I wanted to know if they'd be compatible.