Is deliding a i7 8700k to cool w/ Noctua NH-L9i feasible?

[SpaceMachine153]

I am planning to build an ultra-compact hackintosh for a family member. I want to use the Streacom F1CWS Evo as the case while packing the absolute most performance possible within the extremely tiny chasis. The Noctua NH-L9i is the best CPU cooler than can fit within the case and I want to use an i7 8700k as the processor. On the cooler's TDP chart it says it does not support the i7 8700k, but if I were to delid the CPU then undervolt it do you think I may be able to use it with that cooler. I understand deliding can decrease temps by 10-20 degrees C and with an undervolt that may be even greater of a temp reductiuon. Would I be able to use such components without running into fan speed/thermal throttling issues?
Thanks,

[Arya]

At a glance? No. There's no way to make an 8700K work with such a small heatsink. Not even with de-lidding or an IHS swap. The problem is the cooler itself and the confined space. The cooler can't dissipate enough heat, and without proper airflow the air inside the case will heat up. That'll ruin the efficiency of the heatsink and probably overheat the CPU and the GPU.

De-Lidding isn't a simple process.

All it does is improve the heat transfer between the CPU and CPU cooler. And while it can make a difference, how much depends on the CPU cooler design and how hard you run the CPU. If you have an extremely effective CPU cooler, sure enough you'll see a major drop in temps at peak load. Changing the IHS also helps enormously.

I saved 8-15 degrees, But I run a Noctua NH-D15 with Noctua IP52 Industrial Series fans. And that's a best-case scenario: the most powerful air-cooler on the planet, with the most powerful fan on the market, with a 98% silver IHS, the best Liquid Metal available and the best Thermal Paste.

With an underspec heatsink you may not notice a difference at all. And the whole thing will be compromised by a lack of case airflow.

Heatsinks don't magically make heat vanish. They release that heat into the surrounding air, inside the case. If the case isn't free-flowing enough, hot air will pool around the CPU and GPU. The hotter the ambient air the less-effective the CPU cooler becomes, and eventually you can create runaway overheating.

Solution? You *can* build a compact PC with enormous cooling. But ultrathin cases are out of the question, I recommend a Corsair Carbide AIR-240 running a 240mm radiator for the CPU. It's not as tiny, but it's still very compact. And you can't get much smaller than that and still run a CPU of this calibre.