system
Given the following post, respond as if you're commenting on Reddit:
human
Why do electron holes move 2x slower than electrons?

Electron holes are just places in the lattice where electrons aren't present, so why is the carrier mobility around 2-3x less for electron holes compared to electrons? I never quite understood why.

It obviously has massive effects in electronic design like VLSI gates and power electronics.
gpt
This is only the case for silicon.  There are many materials where holes have a lower effective mass than electrons.  The relative speed of each depends on the relative curvature in Energy vs. Momentum of the possible states in the conduction band vs the valence band.  In other words, it depends on the landscape of valid quantum states for the two different objects.