It's arbitrary. If you count Core i series from Nehalem, Westmere is 2nd so Sandy Bridge is 3rd. Count for * bridge, Sandy is 1st. Additionally Zen+ is 2nd and

It's arbitrary. If you count Core i series from Nehalem, Westmere is 2nd so Sandy Bridge is 3rd. Count for * bridge, Sandy is 1st. Additionally Zen+ is 2nd and it's least improved generation in this time. My general preference: buy Tock generation (but Intel recently no Ticks for desktop, AMD does Tick+Tock on Zen2)