
The Stack
M5 Ultra reviews: local AI's ceiling is memory, not compute
Apple's local-AI pitch finally met a measurement harness this weekend. The verdict is not about how fast the GPU draws tokens — it is about how fast the machine can read, and how much it can hold while it reads. Federico Viticci spent four days running the top M5 Ultra Mac Studio with 256 GB of memory against an M3 Ultra with 512 GB and his own RTX 5090 desktop, on identical model files and the same runtime. Tom's Hardware, PCMag and Tom's Guide published their own reviews the same day, and the










