[Dylan16807]

For what it's worth I got about 196 and 131 for the original y and w, and after adding __slots__ (with comma) I got 186 and 123.

[kragen]

The fact that the difference is 10ms and 8ms respectively suggests that the speedup of attribute access isn't what's showing up in your measurements. In one case we access the slot "a" once; in the other case we access it five times. How can that be a 20% difference?