Overclocking the Intel 8600K - Delidded on Air and Water

Author:Kyle Bennett

Date: Wednesday, October 11, 2017

We've gotten to spend some quality time with our Intel Core i5-8600K Coffee Lake CPU, and of course we have spent our time finding out just how far we could push the processor's clock under both Air Cooling and Water Cooling. We relid and delid as well. The results look to be very promising for the overclocking enthusiast and gamer.

Our Intel Core i5-8600K

First and foremost you can read our review of the Core i5-8600K at 5GHz and see how it fares in terms of IPC advancement. In that review we found no IPC differences between Coffee Lake and Kaby Lake CPUs. For all intents and purposes for those interested in performance, the 8600K is nothing more than a Core i5-7600K with two extra cores stitched on. The discussion thread about that review is located here.

Our 8600K used for testing is an engineering sample that was sourced outside of Intel. Intel no longer samples HardOCP CPUs for review. I would not suggest that the ES CPU we are using here is a "golden sample," and it has not been my experience that CPUs even directly sampled by Intel have been golden samples. That said, this is not a retail purchased sample like we like to try to test with here at HardOCP. However, had this not been an Intel "paper launch" for the most part, we surely would have. The picture above is our processor after relidding.

Our Testing Platform and Cooling Solutions

Air Cooling

For our air cooling hardware we used the Thermalright True Spirit 140 Direct. This air cooler sells for $46 on Amazon, and ships with a single 1300RPM fan. We wanted to use a Push/Pull fan configuration popular among enthusiasts, but I did not have another matched 1300RPM fan, so I used two 120mm 1650RPM fans from XSPC. This still makes for a very quiet configuration.

We are using Prolimatech PK-1 TIM which has a thermal conductivity of 10.2 W/m-C. Above you can see our mating surfaces.

I would suggest that the Thermalright True Spirit Direct 140 represents one of the least expensive cooling solutions that you can purchase to highly overclock the 8600K.

Water Cooling

The Water Cooling system we are using was provided by XSPC, and it represents the other end of the cooling spectrum when it comes to dollars spent. The loop's main components are and XSPC RayStorm waterblock, an XSPC RX480 4-fan copper radiator, and an XSPC D5 Photon Reservoir/Pump Combo V2.

All this cooling adds up to about $400 before fittings, tubing, fans, and couplings and represents some of the most expensive cooling you could use to overclock the 8600K.

We also used Prolimatech PK-1 for our TIM as well with this cooling system.

Motherboard - RAM - PSU

We are using the Gigabyte Z370 Ultra Gaming motherboard, with F5 UEFI. While not a motherboard marketed as overclocking hardware, it has done very well.

Our RAM is a Corsair Vengeance LPX 32GB DDR4 DRAM 3600MHz C18 Kit. For this testing we used only two DIMMs at 3600MHz with 18-19-19-39-2T timings. We did try for a bit to get our 4000MHz kit up and running, but was never successful. That said, we did not put a great amount of time into UEFI tuning in order to make it work.

Finally the power supply we are using today is the Seasonic PRIME TITANIUM 1000 SSR-1000TD.