Loading times (games, apps, OS), are mainly bottlenecked by the hard drive more so then the RAM, so loading times wont be effected at all. The only differences you may notice is a slight increase in gaming performance, maybe 1-3fps, since the RAM can be used by the game much faster, causing less slow downs when tis trying to read it.
And you overclock the RAM as you overclock the bus of the processor, or by lowering the RAM divider.