14 DAY TRIAL // Intel and Advanced Micro Devices seem to be going back and forth as far as their stance in regard to overclocking. Initially, they were against it, then they gave in to public pressure and started encouraging it, and now they are, or at least Intel is, moving back towards the first position.
While Haswell CPU can definitely be overclocked, that only goes for the ones with a K suffix, the K-Series as it were.
The non-K chips are reportedly meant for "the business and consumer market where overclocking is generally not performed," so they don't need overclocking anyway, or so Intel would imply.
It's also worth noting that K-Series CPUs lack the TSX extensions, as well as the VT-d device virtualization and vPro management features that business/cloud customers appreciate.
Clearly, Intel is trying to section its processor lineup, and to make the best of each line of chips, now that desktop demand is dropping.
After all, K-series chips cost $20-30 / €20-30 more than non-K units.