Who is Ryan?

The link I posted was to demonstrate total latency as related to memory speed and timings. You can see in the chart that as you clock higher, you can still achieve the same overall latency at various CAS settings, etc. When DDR3 emerged, it started at DDR3-1066 and 1333 with a CAS latency of 8 or 9. Already you can see that we have come a long way from that and of course there is overclocking too, so when you buy a CAS 7 or 8 module, you still may achieve CAS 6 at XX speed through overclocking which could put you in the green on the chart.
Overall latency is what matters to your applications, not the MHz/CAS setting of the ram. Keep the overall latency as low as possible and you have the best results.