Whats the difference between these speeds/timings and would it be noticable in a gaming machine? I've seen the 1600Mhz at £57 for 16gb, vs £73 for the 2400Mhz. Isn't the 2400Mhz an overclocked speed or something? I've read some reviews that some people can't even boot when setting them to 2400Mhz?