Overclocking The Core i7-5775C
We also spent some time overclockng the Core i7-5775C, to see what additional horsepower the CPU had lurking under its hood.
Overclocking a Core i7-5775C processor is exactly the same as any other pervious Haswell-based Intel K-SKU processor. Because the processor is unlocked, it’s simply a matter of altering a few multipliers, massaging a few voltages, and dealing with the heat, of course.
We took a conservative approach to overclocking the Core i7-5775C to give you all an approximate “worst case scenario”. Our results should be repeatable, assuming you’ve got similar hardware. You shouldn’t need exotic cooling to pull off what we did here--we used a Cooler Master air-cooler with the motherboard and processor installed in a mainstream NZXT case.
To see what our sample could do, we manually cranked the core voltage up to 1.4v and shot right for 4.5GHz, but it wasn't happening. We could get Windows to boot, but couldn’t get the system stable with our air-cooling setup. We experimented with different voltages, but it was too much for our setup. Things were better at 4.4GHz, but still weren’t completely stable. Tooling around Windows was fine, but the system would lock under load. Ultimately, we had to settle for 4.2GHz, with a CPU core voltage of 1.4v. That's an increase of 500MHz over the default boost clock, but not that impressive versus something like Devil's Canyon.
We monitored temperatures while overclocked and didn’t see much improvements over older Haswell-based processors. With our particular setup, while overclocked, the CPU would idle right around the 44’C mark. But under 100% load, temps would shoot up to the high-80’C range rather quickly. With more powerful cooling, we’re sure a hardcore overclocker could get more out of the CPU. While overclocked, we saw nice improvements in performance, as you can see in the Cinebench screenshot and Crysis data above.