Gemma 4 is not a drop-in upgrade. This guide covers what changed architecturally, the full benchmark comparison, VRAM requirements by model size, and exactly what code you need to update when migrating from Gemma 3.

Developers searching for Gemma 4N won't find a named model. Here's what replaced it, how Per-Layer Embeddings carry forward from Gemma 3N into Gemma 4's E-variants, and which model to run on your hardware.