LGA 1156 Memory Performance: What Speed DDR3 Should You Buy?


We looked at different memory speeds for the LGA 1156-based Core i7-870 and chose to run DDR3-800, -1066, -1333, and -1600 at fast, as well as relaxed, timings. Although the differences were typically very small, there were a few applications that obviously benefited from faster memory. This wasn’t surprising, as we already did similar comparisons on most of the other popular platforms:

DDR3 Memory Scaling: Intel’s Core 2 Quad Examined

Core i7 Memory Scaling: From DDR3-800 to DDR3-1600

DDR3 Memory Scaling on AMD’s Phenom II X4

In all cases, we’ve seen significant performance differences when looking at the synthetic or low-level benchmarks. Memory bandwidth does increase considerably if you speed up the memory transfer rate, and tightening timings also improves performance by cutting latencies. However, only a marginal fraction of these benefits actually arrive at the application level. Even going for the fastest memory available will give you a performance boost that is probably smaller than the effect a faster processor speed bin would deliver.

Nevertheless, there are some applications that are more sensitive to memory performance differences than others. Some 3D games (Left 4 Dead in our case) show a noticeable performance boost, likely because it isn't being bottlenecked by graphics performance. Memory-intensive applications, such as Adobe Premiere Pro CS4 and WinRAR, ran quicker, as well. However, the majority of our benchmarks saw little to scarce performance improvement when going for faster memory, so we tend to stay with our original recommendation: go with brand-name memory at mainstream speeds, which still are in the DDR3-1333 space.

However, memory prices have dropped quite a bit, making even DDR3-1600 products more attractive and bringing even some DDR3-2000 products within range. We believe that it’s acceptable to spend a little more on faster memory today if you’re about to invest in other valuable components. Here is our recommendation list (in this order):

  • Make sure you have 4GB of RAM. Two 2GB DIMMs are favorable to ensure you can use the tightest timings.
  • Make sure you pick a branded product of at least DDR3-1333 speed and timings of CL8 or faster.
  • Go for a faster product if you find DDR3-1600 memory that provides the same timings as your preferred DDR3-1333 RAM kit at only a little price premium. Don’t do it if you could get a faster processor for less or the same extra money.