Intel Core i9-7980XE And i9-7960X - Overclocking And Power Consumption
With chips as large and complex as the Intel Core i9-7980XE and 7960X, power and cooling considerations are very important when overclocking. In their stock configuration, both of these processors are rated for 165W, but power consumption and heat output can shoot up considerably when the chip is pushed well beyond spec. As such, Intel has incorporated options to increase voltages and specify peak current thresholds too. The threshold options and power/heat considerations add some wrinkles and complexity to the overclocking process, if you're looking to squeeze every last MHz out of a Skylake-X chip, but we still found overclocking it to be relatively easy and fruitful, even with a mainstream, tower-type air cooler.
With proper cooling and a moderate voltage bump in the 1.35V range, we suspect many Core i9-7980XE processors will be able to hit 4.1 - 4.3GHz with quality air or liquid cooling. With more powerful cooling and some additional voltage though, we're certain higher clocks will be possible. Although the options are there to disable SpeedStep and various C states, overclocking Skylake-X is really as easy as finding the right combo of voltage, BCLK, and peak Turbo frequencies. By altering those options and leaving SpeedStep, etc. enabled, the processor can still clock-down when not under load, minimizing total power consumption and heat output when the CPU isn’t being fully utilized.
We were able to take our particular Core i9-7980XE up to 4.1GHz all-core boost frequency using 1.35V and a peak, all-core turbo multiplier of 41. At that speed, however, we were pushing the limits of the platform as temperatures would spike above 90ºC, and invoking a multi-threaded benchmark that whacked every core would cause a system shutdown. Surprisingly, Our Core i9-7960X wasn't quite as overclock friendly. With fewer cores to power and cool down, we thought we'd get even higher frequencies out of our 7960X, but it wasn't fully stable at 4GHz, so we had to settle on an all-core max turbo clock of 3.9GHz, again with 1.35V.
Before wrapping things up, we'd also like to talk a bit about power consumption. Throughout all of our benchmarking and testing, we monitored how much power our test systems were consuming with a power meter to compare and contrast the results. Our goal was to give you an idea as to how much power each configuration used while idling at the Windows desktop and while under a heavy CPU workload. Keep in mind, this is total system power consumption being measured at the outlet with only the processor loaded and not the the individual power of the CPUs alone.
These power consumption numbers are somewhat shocking. Though the Core i9-7980XE and Core i9-7960X have 60 - 80% more cores than the Core i9-7900X (18 and 16 cores vs. 10 cores), they consumed only 27 - 28 more watts under load, and they used less idle power as well. After reviewing the Core i9-7900X, we thought the additional cores on the higher-end Core X-series processors would push power consumption much higher, and potentially surpass Threadripper, but that was not the case.
We pinged Intel to see if there was aggressive binning used when choosing dies for the high-end, many-core Core X-Series processors, but haven't gotten an answer just yet.