The Dominator series of memory from Corsair is one name that comes to mind when you're thinking of performance memory. While out of reach for many people due to the price the modules tend to be at, if you wanted performance they're a set worth looking at.
Expanding the lineup we see that Corsair has added a PC3-16000 kit which offers a stock clock of 2000MHz. This for most people is simply unnecessary. But if you're serious about your benchmarking or simply want the fastest stuff on the market, they could be worth looking at.
What we'll do is have a look at the package before checking out the modules and see what exactly they're capable of before seeing what 2000MHz looks like and what it means in the performance department.