As of right now I do not believe Generation Zero has a framerate limit, causing stress on the CPU and GPU.
With an intel i7 6700k, I end up with 60-80% cpu usage and cpu temp of 97 degrees Celsius, with a closed loop water cooler. Capping the frames to 75 via third party program reduced the temperature during gameplay to 70-75 degrees celsius
CPU: Intel I7 6700k
GPU: RTX 2080
Motherboard: Asus Z170-A
RAM: Patriot Elite Viper 8gb x2, 2400mhz
There must be something wrong with heat transfer between CPU and water block, or the fans (or water pump) are not working at 100% speed.
I have i5 4670K running at 4200MHz (3400 standard) with Corsair H90 (single 140mm fan) cooler and it hardly reaches 55°C in GZ (all graphics settings set to ultra/high/on).
The issue is with your PC since i have i5-6600K @ 3.9Ghz with Arctic Freezer i32 CPU cooler (push-pull fan conf) and max what my CPU reaches is 59°C during GZ with ultra settings @ 1080p (80-144 FPS).
Replace thermal paste between CPU die and AIO pump’s copper plate. Also, clean your system of dust and when needed add/upgrade case fans.
FWIW, the CPU could be overclocked hard (but likely not stable then during thorough stress testing) or with way too much voltage. But these temps should show in other games and similarly demanding workloads. Whatever it is, it is not healthy. Be it overclock/voltage, cooler mounting, state of the AIO cooler/pump, or case airflow.
EDIT: I could be a combination with bad TIM (thermal interface material, -> paste) below the CPU heat spreader. My brother had to delid lately as the chip just got too hot. And when I had delidded mine, it went down ~25°C. This is an extreme difference but it seems that particularly the 6700k benefits from delidding.
Sir, please try this… Simple Troubleshooting When Game Runs Poorly
It helped for several people.