SiSoft Sandra has a couple excellent memory benchmark tests, and you can compare them with other systems, although the comparisons they have are a little off from the real thing. Also, I believe PCmark has a memory bandwidth test.
MCH 1333 vs 1600 and 1T vs 2T? 1333 will beat 1600 and 1T will beat 2T.
The question should be, will the settings effect your your overclock and if so, will a a faster memory subsystem at a slightly slower cpu speed beat a slower memory subsystem at a slightly faster cpu speed?