I was under the impression that was only an issue for Vista users and wasn't necessary for 7.
3 things for the OP if he's sure he's using 64: The first is the msconfig suggesion above.
The second is to ensure Memory remapping is enabled in the Bios.
The third is to pull the HSF and processor and ensure there are no bent pins in the socket.
also - I have RMA'd OCZ memory in the past. AAMOF, they sent me the replacement in the RMA package so I was never without.