Gaming tests
We could possibly engineer low-resolution situations where faster memory shows a reasonable increase in performance. That, however, would be semi-pointless with a GeForce GTX 780 Ti in tow. We've therefore run three titles at 2,560x1,440, matching the settings used in graphics-card reviews, and the results show a small (visually unnoticeable) difference.
You would probably need DDR3-3,000MHz-plus memory to show a difference when gaming at proper resolutions and image-quality settings.