Hashboard L3+ (S) is the old PCB and could handle Overclocking up to 600 MHs Hashboard L3+ (N) is the new PCB and could and is very poor in Terms of Overclocking (around 540 Mhs only)
So be aware when overclocking newer L3+ they have changed the Boards somewhere in early 2018.
Wow, bastards took out nice polymer caps for aluminum ones. That is saving them like 25 bucks per board.