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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  • ipkh - Monday, June 11, 2018 - link

    The multiplier chart doesn't make sense.
    The single core is 5Ghz, but Intel is quoting 4.7 Ghz all core and you're showing 4.4 identical to 8700K. I understand the base frequencies are the same, but the default multiplier for the 8086K should be higher. Is this a possible bios glitch or is the multiplier chart in the CPU not correct?
  • Hxx - Monday, June 11, 2018 - link

    Boost frequencies are all the same on 5 cores. there is a youtube video with somebody testing this chip on a z370 gaming 7 and you can clearly see in that video that boost is the same on all cores except 1. Intel = lame.
  • Ian Cutress - Monday, June 11, 2018 - link

    Where is Intel promoting 4.7 GHz all core?
  • HStewart - Monday, June 11, 2018 - link

    One thing that is strange is the name - the Original IBM PC that started this whole PC industry used the intel 8088 processor and not the Intel 8086 processor. The difference is that 8088 has 8 bit external and 8086 has 16 bit external - But CPU's used 16 bit internally. No internal Floating processor until the 386 line.

    But it wild that it been 40 years - I have an original IBM PC - in my downstairs closet, I remember while at Georgia Tech - putting a 2Meg Ram card into and booting up to 1.4Meg ramdisk and loading Microsoft C 3.0 compiler on it.

    As for new one - it would be cool if they actually included the original chip also as part of collectors edition.
  • AsParallel - Monday, June 11, 2018 - link

    8088 shipped in 79, was a variant of the 8086. 8086 was the first to 1M transistors
  • peevee - Monday, June 11, 2018 - link

    "No internal Floating processor until the 386 line."

    486. 386 still used 387 AFAIR. There were even 487, but it was just renamed 486 to be installed with 486SX.
  • HStewart - Monday, June 11, 2018 - link

    Yes I forgot that - the 486 was the one with Math Coprocessor.
  • AsParallel - Monday, June 11, 2018 - link

    Addition. The 8087 was the floating point coprocessor for the 8086/88
  • 29a - Monday, June 11, 2018 - link

    You didn't put 2mb of RAM in an original IBM PC it supported 256kb max.
  • HStewart - Monday, June 11, 2018 - link

    I had a special card in the PC - it was EMS memory - that could also fill up the main system memory to 640kb - instead of normal cache mode use by the card - I configured it as ram drive. Memory above 640Kb was directly accessible by the system.

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