They discover the problem of the i9

If you have read our review of the i9-9900K, you will have noticed that the processor can easily exceed 90 degrees in full workload with a 5 GHz OC. Professional overclocker Der8auer discovered why these processors get so hot..

The i9-9900K turns out to have a bad weld

Der8auer wasted no time in opening a 9th Gen Intel Core i9-9900K, a notable chip in part because it is the first conventional 8-core 16-core desktop CPU. The 9th generation Core series also marks the return to the use of a soldered thermal interface material (STIM) between the CPU matrix and the IHS, rather than a traditional lower quality thermal grease. However, Der8auer discovered something interesting that makes him wonder if switching to a soldered solution was really the best move.

For anyone unfamiliar with the concept of 'delidding', it's all about carefully ripping the IHS out of the CPU array, usually to replace the TIM with some liquid metal. Extreme overclockers routinely do this kind of thing, though so do some enthusiasts who may not be chasing record speeds and benchmarking results, but still want to improve their processor temperatures.

As for the Core i9-9900K, Der8auer noticed that its sample was hotter than expected. So, IHS started to investigate. What he found is that both the metal matrix and the PCB are thicker than the previous generation. This is how the Core i9-9900K compares to a Core i7-8700K, as measured by Der8auer:

Metal matrix and PCB are thicker on the i9-9900K

• I9 9900K core PCB: 1.15mm i7-8700K core PCB: 0.87mm i9 9900K core matrix: 0.87mm i7-8700K core matrix: 0.42mm

Der8auer assumes that the added thickness of the CPU as a whole could hurt temperatures. Since the chip is thicker, the heat dissipation is worse. So what the famous overclocker did was polish some of that 0.87mm silicon chip to make it thinner and improve heat dissipation. The results are the following.

Der8auer was able to reach temperatures 13 degrees lower than in a soldered i9-9900K, polishing the chip and adding Thermal Grizzly Conductonaut thermal compound.

It appears that the Delidding process has become more dangerous with the solder added to the mix. What is clear is that Intel could have improved processor temperatures with better soldering and a thinner array and PCB. Recall that the i9-9900K processor has a maximum operating temperature of 100 degrees, and in OC mode it is dangerously close to those numbers.

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