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.
I've had my Noctua CPU fan for more than 15 years, never made a squeak or a noise. And I still get free upgrade kits from them to accommodate for new CPU platforms. Just have to send them a request. So I'd pay the price anytime.