Definately a 2x8GB set, the Tridents, mentioned above are a great choice, but what all do you do with your rig, just wondering? if basically email and surfing, will be wasting your money, if gaming and multi-tasking then 2400 would be a good choice....Big thing is don't waste money that can be used elsewhere for something you need
The Trident's are shown as $169.99 at the Egg, not sure of your budget but there's the Ripjaws X in 1866 for $134.99 (F3-14900CL10D-16GBXL) which is also a good set at a lower price, the Tridents are also available in 1866, $164 and 2133 at $166
You'll be fine w/ that set, The RJs are a great set also....think I've used most all of GSkill sticks up through 2400, still a few 2666 through the 3000 sets I haven't used yet - leaning towards the 2800- 32GB set for my Haswell
Thats the prformance factor playing in the 2133/9 equate to a very tight 1600/7 where the 2133/11 is a to a staid entry level 1600/9....if thinking performance and the 2133/9 isn't in the budget look to 1866/9 which will outperform the 2133/11
Are they an 11 set running at 11, can check in CPU-Z the memory tab, should show freq at 1066(7) and the timings it's at, could also be the 2133/11s are in with the CR at 1 opposed to 2...could also be a very strong set of 2133/11 and the 1866/9 was a weaker set or not set correctly.....DRAM is no different than CPUs, there are some that are very strong, others are 'normal' and then there's weak ones and a lot of different factors can play in....without taking each individual factor into effect, can generally only 'speak' of generalities when comparing DRAM
Have you tried any of these on a Haswell, or are you simply relying on benchmarks? I'm running an i5-4670k on the Z87-GD65 Gaming board, and the real-world differences were pretty obvious. Haswell handles memory differently than previous CPUs....