Lower timings or latency is better, since The timing is the amount of time it takes a the data to travel from where it started to its destination, lower time = faster speed, I believe 2-2-2-2 is be best but i have seen 1-?-?-? before on like TGH.
My RAM has been known to run with something like 1.5-x-x-x, but that's only if you're lucky. I read somewhere that someone had gotten it to run with that.