@Tate-A AVX (advanced vector extensions) are additional cpu commands in recent processors that more efficiently perform some math operations. They make plotting & mining faster.
When plotting the plotter writes "stagger" number of nonces at a time, so total nonces needs to be a multiple of stagger.
Stagger is how the nonces are organized - the higher the stagger, the more optimized the plot is, and the faster it will be mined.