Basically just the CPU fan, case, and PSU (if you're lucky). If someone can figure out how to get Doom running on just those 3 things, young people will be able to ascend.
And awesome warranty and customer support. Plus free mounting upgrade kits if you upgrade your CPU
Edit: the upgrade service:
https://www.noctua.at/en/forms/mounting-kit
I used it once, and I received the new mounting hardware without any issues