You have \\\"K\\\" ones for that

While Haswell CPUs are not that impressive when it comes to overclocking or at least not when compared to Ivy Bridge CPUs, it still can be done and enthusiast market and overclocking community will certainly do it. On the other hand, Intel claims that non-K chips are meant for "the the business and consumer market where overclocking is generally not performed" and thus do not need overclocking anyway.

On the other hand, K-series CPUs lack the TSX extensions, VT-d virtualization and vPro management that have their own appeal but are exclusive to non-K CPUs aimed at business/cloud.

Of course, Intel do not clearly forbid overclocking as the wrath of that community is certainly not something that they would want and need. Usually, K-series Intel chips are around US $20 to $30 (€20 to €30) more expensive than their non-K counterparts.

Source: Softpedia.com.