Overclocking & Test Setup
If we learned one thing from out overclocking efforts, it's that Intel's thermal throttling mechanisms work great. And often. Even slight voltage increases result in large temperature increases. We found that adjusting the VCCIN voltage (voltage going to the processor) in tandem with VCORE adjustments (voltage to the cores) delivers the best results. It's even possible to generate higher multi-threaded performance scores in some benchmarks, like Cinebench, at the same frequency but with increased VCCIN voltage.
We raised VCCIN up to 1.9V, though this does cause thermal output to increase. We also found that up to 2.0V is "generally" safe if you are using water cooling. However, we lowered the VCORE to a mere 1.1V to combat heat. That gave us a semi-stable 4.5 GHz overclock; we were able to run a wide range of heavily threaded workloads, though extended AIDA stress tests exposed throttling. We decided to stick with a 4.3 GHz all-core overclock (84-88°C) because we found that to be the safest setting that wouldn't trigger the aggressive throttling algorithms. The -7960X is very sensitive to increased voltages, and even bumping up to 4.4 GHz resulted in nagging throttling during stress tests.
The processor will throttle if it overheats, but Skylake-X motherboards also throttle if the package power exceeds a defined threshold. With our MSI motherboard, that ceiling lands in the 300W range. We can remove the power restrictions via BIOS manipulation and pull more than 400W through the package, but we shied away from that because we want to test this processor in the future.
We also tested with both the AVX and AVX2 offsets at the Auto setting. The offset automatically reduced our AVX frequencies to 2.4 GHz. We didn't spend too much time tuning this option due to time constraints, but given the platform's high power consumption and thermal challenges, the dual-headed offsets are a welcome and needed feature.
Be sure to bring a custom loop if you plan to overclock. Also, we advise air or water cooling on the power delivery subsystem. Make sure to use a power supply able to deliver a minimum of 20A on the 12V rail. We've heard reports of up to 530W flowing through the eight-pin EPS cable, so a beefy PSU is a must.
Fine-grained tuning will yield better overclocks as we all acclimate to tuning Skylake-X. However, throttling happens any time you take a wrong turn with your settings. A lot of trial and error is required in order to get more from these components.
|Test System & Configuration|
|Hardware||Intel LGA 2066Intel Core i9-7960XMSI Xpower Gaming AC 4x 8GB G.Skill Ripjaws V DDR4-3200 @ 2666 and 3200 MT/sAMD Socket SP3 (TR4)AMD Ryzen Threadripper 1950X, 1920XAsus X399 ROG Zenith Extreme4x 8GB G.Skill Ripjaws V DDR4-3200 @ 2666 and 3200 MT/sIntel LGA 2066Intel Core i9-7900X, i7-7820XMSI X299 Gaming Pro Carbon AC4x 8GB G.Skill Ripjaws V DDR4-3200 @ 2666 and 3200 MT/sAMD Socket AM4 AMD Ryzen 7 1800XMSI X370 Xpower Gaming Titanium2x 8GB G.Skill Ripjaws V DDR4-3200 @ 3200 MT/sIntel LGA 1151 Intel Core i5-7700K MSI Z270 Gaming M72x 8GB G.Skill Ripjaws V DDR4-3200 @ 2666 and 3200 MT/sAll EVGA GeForce GTX 1080 FE 1TB Samsung PM863 SilverStone ST1500, 1500W Windows 10 Creators Update Version 1703Corsair H100i v2|
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