scorpian61 :
When you say, "unless your overclocking", do you mean I have to overclock the 1600mhz ram to 1600mhz or something?
Basically, yes. Your motherboard will not set the ram to 1600mhz by default. It is most likely 1066, or maybe even 1333, depending on the processor you are going to run. If you want the memory to run at 1600, you will have to "overclock" it to that speed.
Now, what the other guy is saying is the reason most people buy 1600mhz memory is because they plan on overclocking the processor.
When you overclock by way of the FSB, you also at the same time start raising the memory speed. So if your stock memory speed is 1333, and you start raising your FSB to overclock the processor, and you have 1600 ram, you should not have to worry about pushing your RAM farther than it is rated, and thus encountering system instability due to the RAM being clocked past what it is rated to run.
But, if you are not planning on trying big processor overclocks, just buying 1600mhz ram for sake of buying 1600mhz ram and wanting to simply run the ram that fast is a waste of money. There is no speed advantage in doing this. In fact, what you should do is try to match your RAM to your systems running bus speed, and then look for RAM with the tightest or the fastest timings. For instance 1333mhz RAM with timings of 6 is going to have better performance than 1600mhz ram with timings of 8. Notice RAM that runs at faster bus speeds needs also longer latencies. So, there is a balancing factor you have to consider. If you are overclocking, most good memory will run over it's rated speed slightly for mild overclocks, but not for more aggressive overclocking.
You can buy the higher bus speed RAM than your systems default settings, and run at higher bus speeds, but if that higher bus speed is arrived at by using longer latencies, what is the point??????(unless, like I said, you going to be doing some pretty decent overclocking)