Quoting myself from another thread on this subject:
You aren't going to "feel" the few percent speed increase that you would get from faster RAM. That doesn't mean it's not there. It just means you probably shouldn't spend a lot of money to get it unless you are already spending big money on your system. Some people spend $500 extra on a CPU to gain maybe 5% performance , $1000 on water cooling to gain another 10% over air cooling ... In that case, spending a few bucks more for faster RAM would definitely be worth it. It takes a pretty big percentage increase in performance before you can "feel" it. You probably wouldn't feel a 20% CPU overclock in most cases if you didn't know it was there, but we are all doing that one.
As for the timing VS clock speed argument: Just so that you have a better understanding of what you are looking at. If you don't already know, the numbers that you see regarding timings are measured in clock pulses. As your RAM frequency goes up, clock pulses get shorter.
SO if your 1333 Mhz RAM has a timing of 7 (for example).
7 clock pulses at 1333Mhz = 5.25 nanoseconds(ns)
That means your RAM needs 5.25ns to do that type of command. (let's assume that this is the best your RAM can do at 1333Mhz)
A Timing of 7 at 1600Mhz would actually be much shorter (quicker) than a 7 at 1333Mhz because 7 clock pulses at 1600Mhz = 4.38 ns. This means that your RAM will not be able to do this command since it isn't allowed enough time to do what it needs to do. A timing of 8 at 1600Mhz is still too quick at 5ns, therefore you would need a timing of 9 at 1600Mhz to roughly equal a timing of 7 at 1333. A timing of 9 would give your RAM 5.63ns to do this command which would be plenty of time. This doesn't really mean your timings are looser (Not considering the slight amount of increase since we couldn't get a perfect match)
In short, once you factor all of this in, you are losing very little in the way of timings as you increase frequency. Just because those numbers are getting bigger, doesn't mean the RAM is taking any longer to do those commands. A timing of 12 at 2400Mhz is still a shorter time period than a 7 at 1333Mhz.
That's all only regarding the timings. Timing considerations aside, you are obviously gaining bandwidth potential as the frequency goes up. In real world applications however, increasing the bandwidth only helps for very short bursts of time except in certain applications.
Let's say for arguments sake that your CPU is actually only waiting for data from the RAM about 10% of any given second, assuming that the RAM always has the data that the CPU needs, you will speed things up within that 10% of the time. This translates to a very small performance increase under most conditions. (25% faster RAM would only get you 2.5% performance increase under these entirely theoretical conditions
everything else being equal.) This improvement is not factoring in the latency either which would further reduce that improvement percentage.Edited by merlinx76 - 8/14/12 at 7:43am