I have successfully replaced 2 * 4GB DDR3 1333 MHz RAM (Samsung) with 2 * 8GB DDR3 1600 MHz RAM (CnMemory). Everything runs fine and System Report is displaying the RAM is running at 1600 MHz.
Now I wonder how accurate this report is. I have learned the RAM clock rate is determined by the Front Side Bus (FSB), so I would have expected the new RAM to still work at 1333 MHz instead of now 1600 MHz.
So does System Report report the accurate clock rate of the FSB or does it report the advertised maximum clock rate from the DDR3 RAM somehow?
(I should have done a memory benchmark before the switch, but I really didn't expect these better results).
Best Answer
I have the same machine (MacBookPro8,2). A quick web search seems to indicate that my 2.2 GHz model has an Intel Core i7 2720QM CPU.
According to Intel's specifications for this CPU family, the supported memory types are actually DDR3-1066/1333/1600. (Incidentally, the memory limit is also 32 GB, but this may require more than two slots; I'm not sure.)
Technically, this CPU doesn't have a traditional "front side bus", which is a connection between the CPU and an external memory controller. Its memory controller is integrated with the CPU, meaning that the supported RAM configuration isn't further subject to the specifications of an external memory controller.
So, it does seem like this system plausibly supports 1600 MHz RAM, after all! I'll be sure to keep that in mind when I upgrade to 16 GB. :)
Interestingly, when I open the same dialog in "About This Mac", my system reports that it supports 1333 MHz memory. It seems like it might just report the current memory speed.