A couple tidbits on memory frequencies...
RAM that is rated at a higher frequency - say 2133 MHz. as an example, will also run just fine at lower frequencies such as 1600 or 1866 MHz. The 2133 MHz. is the maximum frequency that the RAM is rated at to run stable. That doesn't mean your CPU can run the RAM at 2133 Mhz. without corruption however.
As far as RAM frequencies for CPU powered desktop PCs, DDR3 RAM running at 1600 MHz. is not a system bottleneck thus going to faster frequency RAM nets almost no system performance improvement and it's a poor financial investment as a result. Your money is better spent on a faster CPU or GPU if you have significant graphic needs.
The only exception to the above info. on desktop PCs is when they are APU powered. Higher frequency RAM up to approx. 2133 MHz. shows small system performance gains because the GPU section of the APU benefits from the faster RAM frequency - up to a point. The gains are small but some folks are willing to pay a premium for them. If however you are going to use a discrete Video card, just run 1600 or 1866 MHz. RAM and use the money for a better CPU or Video card.
While we're talking RAM it's worth noting that RAM latencies mean almost nothing now that we have DDR3 RAM running at 1333 MHz. and higher. Extensive testing has shown that the fastest RAM timings make almost no system performance difference compared to the slowest RAM timings. It simply doesn't matter now that 1600 MHz. RAM is no longer a system bottleneck even on a performance desktop PC.
RAM benchmarks show the "potential" of faster RAM frequency and timings IF the RAM were saturated all the time, which it is not. Thus even the fastest RAM only brings minute system performance gains and is so disproportionately priced vs. actual system gains that it's pointless to buy the very high frequency RAM for other than bragging rights.
Building a reliable PC involves more than just assembling the parts. You need to be able to configure all of the BIOS settings appropriately. This can be quite involved and frustrating as it can require a lot of trial and error with stress testing. It is however often the only means to get a 100% reliable PC.