If you were to purchase RAM of a speed higher than 2133 MHz, you would need to manually over clock it in BIOS in order to utilize the faster memory; otherwise, it will automatically down-clock to 2133 MHz. How to overclock it should be spelled out in your
motherboard manual.
Performance-wise, faster RAM may be of benefit, depending on what you're doing on the system. If you are a heavy multi-tasker, then you would want to get faster RAM. If you're like me and at the most, listen to music while doing one other task, I wouldn't worry about getting faster (more expensive) RAM. If you can get it at the same or very similar cost, there's no harm in getting faster RAM.
-Wolf sends