In our performance tests we checked out the speed of our LGA1155 platform with different dual-channel memory kits from the Corsair Dominator Platinum series. Each kit was tested in two modes: 1) automatic configuring (every timing is set by the mainboard's BIOS according to the XMP data) and 2) highest clock rates and best timings (as achieved in our overclocking tests above) set up manually in the mainboard’s BIOS.
First of all we want to run synthetic benchmarks of memory bandwidth and latency. We will use the memory test from SiSoft Sandra 2013 for that. Using a multithreaded Stream algorithm, it is perfectly suited to modern memory controllers optimized for multi-core CPUs.
The clock rate of DDR3 SDRAM does affect memory subsystem parameters on Ivy Bridge platforms. For example, increasing the clock rate by 333 MHz helps improve the practical bandwidth by 10-20% and reduce the latency by 5-10%. However, the benefits are not so obvious at high frequencies due to poor timings. For example, the practical bandwidth may even lower on transitioning from DDR3-2400 to DDR3-2666. The latency remains the same, though, so faster memory will always ensure higher performance for your computer.
The SiSoft Sandra 2013 results suggest that it makes practical sense to be particular about choosing DDR3 SDRAM modules. However, this is a synthetic benchmark which is meant to measure how fast the CPU can work with system memory. Everyday applications are not so memory-sensitive, yet we want to check them out as well.
Fast memory is indeed appropriate in some situations, especially if its price doesn’t differ much from the price of ordinary products. Memory subsystem parameters can affect the speed of gaming applications, for example.
Of course, it is the graphics subsystem that influences the frame rate the most, but the memory frequency is a factor, too. Fast memory can help you improve performance by a few percent. So again, the choice of DDR3 SDRAM is quite important, especially in terms of its frequency.
There are exceptions to that rule, though. Take note of the performance of the DDR3-2400 kit CMD16GX3M2A2400C10. It is occasionally outperformed by the DDR3-2133 kit CMD8GX3M2A2133C9 because it consists of two 8GB modules which have less aggressive timings than the 4GB ones.