CAS latency, or CL, is the delay time between the moment a memory controller tells the memory module to access a particular memory column on a RAM memory module, and the moment the data from given array location is available on the module's output pins. In general, the lower the CAS latency, the better.
Corsair Dominators usually come from the highest quaality chips available from chipmakers like Micron. In many instances, Corsair Dominators are derived from the highest binned chips available Not certain about G. Skill, but G. Skill uses high quality chips with their performance RAM. Neither Corsiar or G. Skill are chip makers. These company's use chips from Micron (Crucial), Samsung, Elpedia, etc. The RAM will come with specifications regarding speed (data transfer rate), timings and voltage requirements. There should not be a heat issue if used within the Mfg. specs.