Intel's new P67 motherboards allow its LGA1155 Core i3, Core i5 and Core i7 CPUs to clock the memory to speeds up to and including 2,133MHz without the need to overclock. This is despite the fact that the CPU's dual-channel DDR3 memory controller is only rated up to 1,333MHz.
When we tested Intel Lynnfield memory performance, we were left in little doubt that 1,600MHz CL9 DDR3 was the best buy. Beyond this speed, the performance gains didn't justify the price premium of super-fast kits.
However, while Sandy Bridge CPUs are still an evolution from Lynnfield, they're also sufficiently different in their internal design to merit looking at how they handle different memory speeds and latencies.
The aggressive pre-fetching of Intel CPUs has always successfully hidden memory latency and the need for excessive memory bandwidth. However, with an even more aggressive pre-fetcher in Sandy Bridge, and a new architecture that includes an internal ring bus, it's always necessary to have our suspicions confirmed with real results.
8GB and 16GB kits for Sandy Bridge should become common
Memory Performance, Clock-for-Clock
We also pitted our Sandy Bridge CPU against the popular LGA1156 Lynnfield and LGA1366 Nehalem architectures, in order to show how the relative frequencies affected each setup. We adjusted the frequencies of the CPUs to be as close as possible to each other, but check the test setup page for more details about this and our reasoning process.
Finally, we also pitched a basic 4GB dual-DIMM DDR3 setup against a 16GB quad-DIMM kit to see if there was any significant difference in performance. We also wondered if Sandy Bridge systems could handle the extra load of running four memory modules at the maximum memory multiplier.
Hopefully, this wealth of knowledge will make you better prepared for your next Sandy Bridge purchase.