1492 is the max for PPPoE and it is ok to have it at that. It is also good to leave it slightly smaller at 1480 if you want to be more compatible, you won't see any noticeable reduction in speed, and for gaming latency is more important than the 0.01% potential throughput reduction.
Should I increase my default mtu from 1480 to 1492? 1492 being the maximum I can enter.
Would changing it from the default cause problems?
when I did a mtu test it said the value that didn't fragment was 1450. Do I add 28 bytes onto this to get my optimum mtu value and just tpe 1478 into my mtu ...