crookedvulture writes "With its Sandy Bridge and Ivy Bridge processors, Intel allowed standard Core i5 and i7 CPUs to be overclocked by up to 400MHz using Turbo multipliers. Reaching for higher speeds required pricier K-series chips, but everyone got access to a little "free" clock headroom. Haswell isn't quite so accommodating. Intel has disabled limited multiplier control for non-K CPUs, effectively limiting overclocking to the Core i7-4770K and i5-4670K. Those chips cost $20-30 more than their standard counterparts, and surprisingly, they're missing a few features. The K-series parts lack the support for transactional memory extensions and VT-d device virtualization included with standard Haswell CPUs. PC enthusiasts now have to choose between overclocking and support for certain features even when purchasing premium Intel processors. AMD also has overclocking-friendly K-series parts, but it offers more models at lower prices, and it doesn't remove features available on standard CPUs."