Thermal Interface and Extreme Overclocking

(with Alva Jonathan)

One of the big questions surrounding the new CPU is if Intel has decided to make changes to the way the CPU and the heatspreader make contact. The best way to make contact is to use an Indium-Tin solder, or a liquid metal, to ensure that the thermal load from the CPU is taken directly to the CPU cooler. The cheaper method (but more reliable method) is with a thermal paste, which is more resilient to thermal expansion coefficients over the lifecycle of the processor. In a perfect world, we'd expect the highest performance processors to use the solder method while cheaper processors can use a thermal paste. However Intel has been making its processors solely with thermal paste of late, causing extreme enthusiasts to resort to delidding and adjusting the thermal paste with liquid metal. AMD uses thermal paste in its APUs, and we did a delidding guide a few weeks back:

Delidding The AMD Ryzen 5 2400G APU: How To Guide and Results

The Intel method is mostly similar. However, the question for this review was if Intel would change from a thermal paste as used on the Core i7-8700K to a more overclocking and thermally friendly solder for the Core i7-8086K. The idea is that if Intel is geared towards enthusiasts, solder should be used, right?

Making It Possible

For this page, we are extremely thankful to Alva Jonathan, aka ‘Lucky_n00b’, a fellow overclocker and journalist for Jagat Review. I'm known Alva for almost 10 years, and like me, he also purchased his Core i7-8086K during Computex this week, except he went the full beans with delidding and liquid nitrogen. He is allowing us to share his results with our audience, so a big thank you to Alva!


Alva does some impressive overclocking coverage on all the new platforms at Jagat Review (in Indonesian), as well as doing exceeding well at overclocking competitions around the world. This week he scored third place at G.Skill’s live overclocking event at Computex, scoring some nice hardware and a cash prize.

Alva’s Core i7-8086K OC and analysis can be found here (in Indonesian).

Opening Up The Chip

Suffice to say, Intel made zero changes to the thermal interface on the Core i7-8086K. It is completely identical to the Core i7-8700K, using the same thermal goop as in previous generations of chips. For current Coffee Lake processors, removing the thermal goop and replacing it with a liquid metal implementation is generally good for lowering temperatures from 5-15C (depending on the quality of the application) or gaining another 100-300 MHz depending on the voltage response of the chip.

Alva recommends only delidding the processor for more frequency or better thermals if you intended to use more than 1.30 volts through the CPU. At this voltage, with a good ambient cooler, users will start to hit around 80 C when running the CPU at full load (we can confirm, our sample was similar), which is a good point for anyone considering a delid.

With his CPU, Alva achieved 5.0 GHz at 1.20 volts, which was stable enough to run CineBench R15 for a score of 1627 (compared to 1424 at stock with fast memory). The CPU also managed 5.2 GHz at 1.35 volts for a few more points at 1692. He used KingpinCooling KPX as the replacement thermal interface material.

Going Beyond with Liquid Nitrogen (LN2)

Extreme overclocking is an interesting pastime to participate in, however for the users on the extreme edge of the sport, every MHz counts. Not only for cooling but systems are physically modified to add better power delivery or to adjust voltages manually rather than through software. For those that can, it creates a thrill or two.

In Alva’s testing notes, he started with MSI’s Z370 Godlike Gaming motherboard prepped for sub-zero cooling, and used a heavy LN2 copper pot to manage temperatures with the liquid nitrogen. After bring the system down to -100C, he booted with BIOS settings such that the CPU was at 6.0 GHz (60x100), with an uncore of 5.0 GHz and a CPU voltage of 1.70 volts. Don’t try this without sub-zero cooling (!). Other voltages were as follows:

  • SA/IO Voltage: 1.35 V
  • DMI Voltage: 1.80 V
  • CPU PLL Voltage: 2.20 V
  • CPU PLL OC Voltage 2.20 V
  • CPU ST Voltage: 1.35 V
  • CPU ST V6 Voltage: 1.35 V

The CPU was kept in its full 6C/12T mode.

After booting into the OS, MSI Command Center Lite was used to adjust the processor variables (multiplier, base clock, voltage) in real time. The system was cooled down further to its limit, known as ‘full-pot’ liquid nitrogen benchmarking, and the multiplier was raised to find the absolute processor frequency limit for a no-holds barred validation.

The final result? 7309 MHz:

In general, Skylake-based processors tend to see peak liquid nitrogen frequencies around 7.1-7.4 GHz, so this new processor is nothing out of the ordinary. Alva said that he was quite happy with this single chip, however he will need to test a few more to see exactly where if there is variation in the wafer/batch from Intel. When Alva posts his full sub-zero overclocking article, I will link to it here.

Edit: Here is Alva's article -

Intel Core i7-8086K Review Ambient Overclocking and Power Scaling Analysis
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  • mkaibear - Tuesday, June 12, 2018 - link

    "Total flop"

    I suggest benchmarking the CPU in your phone against this CPU and try again.
  • SanX - Tuesday, June 12, 2018 - link

    They mostly serve different purposes and apps and have different TDP. But if you restrict consumption power of Intel processors to the same one of mobile processors then in the same apps it's not clear in advance which one will win.

    Time for ARM to look at the server and supercomputers markets.
  • iranterres - Monday, June 11, 2018 - link

    HAHA. Intel once again trying to fool some people and appeasing the fanboys with something worthless and expensive.
  • xchaotic - Tuesday, June 12, 2018 - link

    So are the regular i7-8600K unable to run all core 5GHz? If so, what't the max stable freq for a non-binned i7-8600K? Personally I went for an even lower/cheaper i5-8400 CPU, but I see why some people prefer to be running max speed all the time...
  • Rudde - Tuesday, June 12, 2018 - link

    I assume you mean the i7-8700k.
    There is a phenomenon called 'the silicon lottery.' Basically, when you buy an i7-8700k, you can't know the max stable frequency. It could max out at 5.2GHz or it could only reach 4.7GHz before going unstable. The thing is, you can't know what you'll end up with.
    This brings us to the i7-8068k. The i7-8068k is pretty much guaranteed to have a max stable frequency above 5GHz. Of course, this matters only when overclocking.
  • Bradyb00 - Tuesday, June 12, 2018 - link

    Is it a lower temp than a 8700k for a given multiplier though? i.e. both 8700k and 8086k at 46x which is cooler? 8700k obviously has to be averaged as not everyone is lucky with the silicon lottery.
    Presumption is the 8086k will run cooler on average due to the better binning.

    In which case I'm happy to pay more to save some degrees in my wee itx build
  • Lolimaster - Tuesday, June 12, 2018 - link

    Why not simply pick the Ryzen 5 2600, same thing with actual lower temps from using high quality solder...

  • TheinsanegamerN - Monday, June 18, 2018 - link

    Depends on the use case. For pure gaming, I'd stick with intel, which is a bit faster now and, if history is any indication, will hold up a LOT better for gaming in 5 years then the AMD chip will.

    Especially if you run games or emulators dependent on IPC (like PCSX2) the intel chip will perform a lot better then the AMD chip.

    There is also the memory controller. Ryzen 2000 improved, but intel's controller is still superior, and that matters for things like RTS games that consume memory bandwidth like black holes consume stars.
  • Stuka87 - Tuesday, June 12, 2018 - link

    Props to Asrock for providing the system so that you could get us stuff so quickly Ian. Not sure why everybody is complaining about the system and cooling that was used. The system was loaned to you so that you could get us numbers fast, which personally I am happy about. Thanks for your hard work Ian!
  • El Sama - Tuesday, June 12, 2018 - link

    This is quite the premium cost for a small increase in frequency that should be close to what you get to a 8700k OCed, an interesting offering regardless.

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