I used to think that it is based on whether you outperformed your current elo in a match. But today I (Silver 2) played a match and got Match MVP in a lobby with 6 players who were Silver 3 and Gold but still didn't get any performance bonu...

I was queueing up with my friends and then as a joke I reported him even though he doesn't hack or say anything toxic (in game chat or voice chat at least.) The next day he gets banned for toxic communication even though he only queues wi...