Delidded AMD Ryzen 9 7900X runs a massive 20°C cooler, calls IHS design into question

Did AMD sacrifice under-load temperature for AM4 cooler compatibility?

Delidded Ryzen 9 7900X

Our launch-day coverage of Ryzen 9 7950X and Ryzen 7 7700X unearths an uncomfortable truth that AMD’s Zen 4 CPUs run hot. Placed under a capable Noctua NH-D15 heatsink, all-core temperature at stock speeds quickly escalates to 95°C. The tech community’s favourite overclocking daredevil, der8auer, has taken it upon himself to see if removing the new IHS and going direct-die cooling is worth it. The answer is yes, as he managed to reduce peak all-core temperature by over 20°C on an overclocked 12-core Ryzen 9 7900X CPU.

In his video, he runs a retail-sample Ryzen 9 7900X at an all-core 5.4GHz with 1.29V. Even decent watercooling is unable to keep the chip the right side of 90°C, he notes, which is entirely within our expectations.

Prising off the rather thick integrated heatspreader (IHS) and cleaning up the CCDs before placing the same cooling on top of a custom-made holding plate, as seen the video grab above, the ‘moment of truth’ reveals temperature drops to below 69.5°C, roundly indicating the standard IHS, designed to maintain compatibility with the AM4 mounting system, isn’t doing a great job.

It is entirely reasonable and proper to see lower under-load temperatures when going straight to the silicon, yet the marked decrease is more than we expected.

Image credit: der8auer

This revelation leads us to believe that, unlike what AMD claims, the latest Ryzen 7000 Series chips don’t need to be running above 90°C when under load. They do so, it appears, due to a particular IHS design, enforced on the AM5 chips due to meeting compatibility with AM4 coolers.

Given der8auer’s results, AMD would have been better served in designing a better-functioning IHS, even if that meant breaking compatibility with extant AM4 cooling. If you have gone to the lengths to build a new socket, use new memory and offer PCIe 5 everywhere, why not go the whole hog and build out the physical CPU better from a cooling point of view?

It’s very unlikely AMD will deviate from the Ryzen 7000 Series IHS for a while – the ‘octopus’ is here to stay – yet don’t be overly surprised if 2024’s Zen 5 takes a different tack.