The overclocking wizards over at Igor’s Lab have been digging into user-reported cooling issues surrounding Intel’s new LGA 1700 socket. While Alder Lake CPUs do run hot under full load, the issue isn’t the heat caused by the CPU. People are discovering the integrated heat spreader (IHS) on the top of the chip is getting warped, resulting in less than optimal contact between the CPU and the cooling mechanism. This of course leads to all kinds of questions about which part is at fault here, as there are a lot of factors that contribute to the amount of pressure applied to a CPU’s heat spreader, and more importantly, where it’s applied.
The main issue with Intel’s new socket is that in order to accommodate the company’s first hybrid CPU architecture, which combines both performance and efficiency cores in one package, the company had to make its CPUs more rectangular than its previous offerings. LGA 1200 and all the consumer CPUs that followed it were basically square, with most of the heat coming from one core in the center of the CPU. With Alder Lake and its hybrid architecture and rectangular shape, it’s more complicated. Before the new CPUs even launched there were a plethora of articles discussing whether or not coolers made for previous CPUs would even be able to cover the areas that needed cooling in LGA 1700, and we reported on it also when we first got a glimpse of the redesigned socket, noting that reusing an old cooler would likely not be effective.
LGA1200’s square design compared to the elongated LGA1700. (Image: Guru3D)
However, the issue that is rearing its ugly head now is warped heat spreaders, which are made from a thin piece of nickel-plated copper and sit on top of the CPU die itself to interface with the cooling mechanism. According to Igor’s Lab, the Integrated Loading Mechanism (ILM) on the socket, which is the apparatus that secures the CPU into the socket itself, is applying pressure in an uneven manner, and the result is curved heat spreaders.
This is a big problem because Igor’s measurements show small but significant gaps can occur between the heat spreader and the cooler that’s sitting on top of it. Although thermal paste can help “close the gap” so to speak, it’s not designed to cover gaps that big, so it’s not very effective. The main cause of this is the ILM is putting pressure on the middle-sides of the socket, instead of the corners as in previous sockets, which is causing the heat spreader to be pushed downward in the center. Another factor which may or may not be contributing here is Alder Lake has a noticeably lower Z-height than LGA 1200, which supported z-heights of 7.312mm to 8.249mm. LGA1700 is thinner, with a z-height of 6.529 to 7.532mm.
A straight edge on top of an Alder Lake CPU that has seen hundreds of hours of operation shows a noticeable concave shape for the heat spreader. (Image: Igor’s Lab)
So, what’s the solution? Igor’s Labs writes that buildzoid at Actual Hardcore Overclockers had a “mod” theory that the issue could be resolved by raising the socket height with washers, which Igor tested and validated. He writes, “washers are simply installed between the motherboard and the ILM, which effectively makes it sit higher and thus exerts less pressure on the CPU in the socket.” To do this mod you will just need to remove the four M4 Torx T20 screws that hold the ILM down, and then insert M4 washers over each of the holes.
The ILM removed and washers in place. (Image: Igor’s Lab)
To see which washer thickness worked best, Igor’s Lab tested a range of sizes including 0.5 mm, 0.8 mm, 1.0 mm and 1.3 mm. In their testing they found the ideal length was 1mm, and anything taller than that provided diminishing returns, and and it also found that anything thicker than 1.8mm was unworkable due to the length of the ILM’s screws.
Once all the washers were tested, the 1mm washer came out on top. In benchmarks it was able to lower the average temperature under load by an impressive 5.76C. This was on a Core i9-12900K with E-cores disabled, and P-cores running at 5.1GHz on liquid. With no washer at all, the CPU topped out at 76.64C, which then dropped to 70.88C with the addition of the washer. Overall, that’s a significant gain in cooling with such a simple modification. The only caveat here is Igor’s Lab says they are not sure if this “situation” applies to all LGA 1700 boards, but it notes that there are only two companies that make the ILM, which are Lotes and Foxconn, so they will try to test more of them in the future.
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