[SOLVED] What's the best CPU I can purchase?

[Energizor]

What's the best CPU I can purchase that would be compatible with my setup?

Specs:
MOBO: Thimphu-K
Processor: i5-7400
GPU: GeForce GTX 1070
RAM: 16gb

 

[Barty1884]

https://support.hp.com/ca-en/document/c05369438

Outright "best", i7-7700K.
Given you won't be able to overclock a 7700K though, the most practical "best" CPU would be a 7700 non-K.

The 7700K does turbo a bit higher, so there's a clock speed gain to be had in opting for the K.... but that might require a replacement CPU cooler too (although the stock may be fine, hard to say).