You don't mention what DRAM, Corsair has a number of sets at 1600 with a CLof 10 and even 11 which is slow...also on DRAM 8GB is good for gaming but not sure where you are....the CPU and GPU shouldn't have any bottlenecks between them
At worst you are Cas 11, and even though it's sub-optimal, you will be just fine. Like Tradesman1 said, you aren't bottlenecking anywhere. You might be able to get better Ram, but I don't think you'd notice any difference. Just because you can benchmark and show a difference, doesn't mean you'll actually see a difference in gameplay.
Well, spend time reading reviews on different Cpu's, video cards, ram, motherboards etc. and you'll start to form your own opinion based on them. Also, spend time reading reviews from different websites as well. Generally, numbers don't lie and you can find what will work for you based on games played or workload needed for parts. I have Tom's bookmarked for reviews, as well as Anandtech; and also have techPowerup listed for a good reviews from other sites directory, as well as their own.
Of course, everyone who posts suggestions on Tom's has their own parts preference/bias as well.
Also, if you build, repair or do upgrades for others, whenever you get your hands on a new component, test it with whatever you can, that and other support is my primary reason for building a Haswell, I'm rather happy with my 3570K