Can they go faster? You bet. The 3960X cranked up to an all-core 4.35GHz using 1.3875V while the 3970X managed 4.275GHz across its 64 threads with the same voltage. Bear in mind we used a Fractal Design Celsius S24 all-in-one watercooler for all tests. Temperatures for both chips were around 80°C at default speeds and 93°C when overclocking.
Performance increases are not linear with frequency because the first 60 seconds is devoted to Blender setup. Platform power comfortably exceeds 500W when overclocked.