I am looking into upgrading my custom built PC's RAM. I use the machine mostly for gaming, but I don't really know a ton about RAM, so I wanted to ask a few questions.

1. The research I've done tells me there is a negligible increase in speed for anything above 1600 MHz. is this true or is it worth the extra money to go higher?
2. Other than drawing more power from the PSU, is there any real difference in performance with different voltages (1.5V vs 1.65V)?
3. most of the kits I've found in the 2x4 1600 range have a CAS latency of 9 and timing of 9-9-9-24. For a significant increase in price (usually about 1.5x), I can get either 8 or 7 and lower timing. Is it worth the cost?

What I am looking for here is someone to give a good explanation of what the different specs represent, and how that relates to the performance of the machine. Specifically, I'm looking for what specs I need to focus on for a good gaming rig. I am NOT looking for a "buy this, it's the best RAM" without an explanation of why. The information will be much more valuable as it will allow me to make my own informed decision.

As they say, give a man a fish, he'll eat for a day. teach a man to fish, and he'll eat for the rest of his life.