Gemma 4 on a 16 GB Mac: the E4B matches the 12B at 42% less RAM and 3× the speed

Google's Gemma-4 E4B posts the same math and factual scores as the full 12B on an M3 MacBook Air — in 6.6 GB instead of 11.4, at 8.2 tok/s instead of 2.7 — so on a 16 GB Mac the E4B is the one to run. This is a size win, not a QAT one: the 12B's own QAT build doesn't shrink or speed it up. Honest numbers, measured under a real 2048-token load.