mrea13 :
So I have a i5 6400 which is 6th gen and I am wondering if i can use that in say a new 8th gen motherboard.
You usually check cpu compatibility list for the motherboard, to find answers to this.
General rule is - 6,7 gen cpus use 1xx and 2xx series boards (7th gen on 1xx series board requires bios update)
8,9 gen cpus use 3xx series boards (9th gen cpu on 3xx series board requires bios update or z390 board).