Does LGA 1151 cooler fit 1700?

No, LGA 1151 cooler does not fit the 1700 processor. The LGA 1151 socket is designed for Intel processors, while the 1700 processor is part of the AMD Ryzen series which uses the AM4 socket. The mounting mechanisms and dimensions of the two sockets are different, so a cooler designed for LGA 1151 will not be compatible with the AM4 socket. It is important to ensure that you have a cooler specifically designed for the AM4 socket if you are using an AMD Ryzen 1700 processor.

Soooo, short story long: I ended up using my old LGA 1151 cooler on my new LGA 1700 CPU. Appart from the fact that it's a small and not very effective cooler that makes CPU hotter than it should, everything seems to be fine.