Right now, each Axis has a two lists of Tick objects (one major, one minor), each of which has 3 Line objects (for left tick, right tick and gridline) and 2 Text objects (for main and secondary label). Constructing Line objects is rather heavy and expensive. Refactoring this code so that each Axis had 3 LineCollection objects instead where only the points of the ticks needs to be updated, sharing all of the line style information, should be much faster.

On the following simple benchmark:

plt.subplots(8, 8)
plt.savefig('test.png')

25% of the time is spent constructing the Line objects. The suggested change above should reduce the number of Line objects from 3*N (where N is the number of ticks, usually a dozen or so) to 3.