According to the reporting originating from makers of factory overclocked PCs, the retail version Intel Haswell series processors are not as good as production samples that many reviewers and overclockers got their hands on before its official release. Processors like Intel Core i7-4770K do not remain stable in the same bumped clocked speed in comparison with pre-production sample counterparts.
Four companies that build systems have confirmed about the retail versions of Haswell not able to maintain stable clock speed as seen on pre-production samples. One of the four companies have said that they had pre-productions samples where they pushed from 3.5 GHz to 4.7 GHz or even 4.8, but even with 40-50 retail versions, they were finding it impossible to overclock beyond 4.2 GHz as it consumed higher voltages and generated unsafe core temperature.
The second company confirmed that there’s a big difference in overclocking potential between the pre-production samples and the retail chips, whereas the 3rd manufacturer said that they won’t be selling any systems with Haswell processors higher than 4.4 GHz as it would not yield stable overclock. It was also been added that Core i7-4770K overclocked @ 4.6 GHz was so unstable that booting to the OS was impossible, and i5- 4670K was restricted to 4.2 GHz as the voltage bumps accelerated, leading to an unsafe temperature.
Intel made the following comment:
the overclocking experience will vary from CPU to CPU, and from generation to generation, due to many different factors. We cannot guarantee a specific frequency. We continue to add new and exciting overclocking capabilities and we expect enthusiasts to be pleased with the unlocked 4th Gen Core processors.”