A lot of people will be using Intel processors made in the past 10 years (Mac and PC). It seems there is a bug in all 64 bit Intel chips that allows a security breach and is now the subject of much activity to get fixes out. Unfortunately the nature of the bug means that there will be a performance hit as software is re-written to account for the bug and the extra software checking will slow things down. I don't understand much of the article but there's more about it in here:-
https://www.theregister.co.uk/2018/0...u_design_flaw/