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: http://valid.x86.fr/2tx32n

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 - http://oc.jagatreview.com/2018/06/intel-core-i7-8086k-extreme-overclocking-7-3ghz-on-msi-z370-godlike-gaming/

Intel Core i7-8086K Review Ambient Overclocking and Power Scaling Analysis
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  • wr3zzz - Monday, June 11, 2018 - link

    K-series CPUs don't come with coolers. Reply
  • rocky12345 - Monday, June 11, 2018 - link

    They used to but Intel coolers are so bad that no one used them so instead of making one that was usable for the k CPU's they just stopped including them. At least the other guys include them still and 2 of the 3 are actually usable as coolers. Personally I would rather have some sort of cooler included so at least would be up and running if the high end air or water cooler was om back order or waiting on shipping at least can get the system built and running. Reply
  • Flunk - Monday, June 11, 2018 - link

    The ones they sent out with the older -K series processors were a joke. My i5-2500K came with a cooler that couldn't even cool it within Intel's specs running stock in a cold room. Reply
  • mkaibear - Tuesday, June 12, 2018 - link

    I'm still using the one which came with my 4790K and it works fine, and the one my 2500K came with also worked fine when I had it, even at 30C ambient temps in the middle of summer.

    Probably an installation error there Flunk.

    (yes, I bought K series processors and never overclocked them, for both of these my intention was to downclock them for reduced heat and noise but never got round to it with the 2500K and the 4790K didn't really downclock very well so I couldn't be bothered!)
    Reply
  • jimmysmitty - Friday, June 15, 2018 - link

    Absolutely incorrect. I installed tons of the stock Intel coolers on i5s and i7s and they work as specified for the stock settings of the CPUs plus were normally very quiet. Reply
  • SirMaster - Monday, June 11, 2018 - link

    "K" CPUs con't come with heatsinks or fans... Neither does the 8700K or 8600K or 7700K, etc. Reply
  • Matthmaroo - Monday, June 11, 2018 - link

    It’s been a while for you , I see - K series cpus have no cooler Reply
  • Memo.Ray - Monday, June 11, 2018 - link

    Memo.Ray - Monday, June 11, 2018 - link
    As I mentioned in my comment in the other article a couple of days ago:

    Intel managed to give away 8086 "binned" 8700K (AKA 8086K) and still make some money on top of it. win-win situation :D

    https://www.anandtech.com/comments/12940/intels-co...
    Reply
  • jimmysmitty - Friday, June 15, 2018 - link

    And you miscalculated because you used the i7 8700 cost not the 8700K cost. They made maybe $300K on them.

    You know I have never seen anyone complain about say a 40th anniversary version of a car.
    Reply
  • just4U - Wednesday, June 13, 2018 - link

    If it were more similar to the 4790K with a better thermal design (think devils canyon..) it's something I'd be interested in over the 8700K. It's not tho… and doesn't even come with a specialty cooler that might peak interest.. but rather "NO COOLER" at all.. I dunno..

    I think Intel missed the boat with this one.
    Reply

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