I just installed 2GB (2x1GB)ram into my iMac Core Duo 2.0 ghz. The memory registers fine and everything, however when the iMac goes into sleep mode and I go to revive it, it just restarts. I had this problem with the first set, so I exchanged it for another set and still have the same problem (problem does not occur with the original 512mb chip). The memory is Mushkin brand DDR2 667 (PC2 5300) Dual Channel. Is there anything I have to/can do after simplying installing the new chips? Thanks.