This set of modules is rated to run at latencies of 9-10-9-27 at 2000MHz right out of the box. Not the best latencies, but most of the modules you can find on line for a reasonable price come with a cas latency of 9. Any lower and the cost for the modules goes up exponentially, it seems. Although the latencies are a little loose, they allowed the modules to reach almost 2200MHz with some QPI and vdimm voltage tweaking.