Hi, iMac 2011 21,5 4GB RAM. I added 2 4GB RAM banks in DIMM1 slots. Now I have totally 12 GB. The system recognized them and memtest passed successfully. Anyway System Profiler shows for those new RAMs this: Dimensioni: 4 GB Tipo: DDR3 Velocità: 1333 MHz Stato: OK Produttore: 0x0000 Codice prodotto: 0x000000000000000000000000000000000000 Numero di serie: 0x00000000 It is in italian, but I hope you can understand the fields. Do you know why and if it is correct that profiler shows zeros in the last 3 fields? Are the memory performances/functionalities affected in some way, according you? Thanks in advance, Dave.