The M4 Mac mini came with a surprise — a slotted and upgradeable SSD. Here's how to install one, get it running, what to expect for speed, and what's happened in the last eight months since upgrading.

For comparison, it’s more powerful than the M3 Max MacBook Pro I reviewed last year, and it’s faster than even the M2 Ultra that you can still buy in a sold-as-new Mac Studio or Mac Pro. That’s just a ...