tl;dr: The M5 Ultra Mac Studio delivers major gains for local AI workloads, with roughly 70% faster token generation and 150% faster prompt processing versus the M3 Ultra, thanks to its new 80-core GPU with Neural Accelerators and 1.2 TB/s memory bandwidth. While an RTX 5090 still edges it out on raw speed, the Mac Studio's unified memory (up to 512GB) allows it to run larger models like Qwen3.8-Flash-Next locally, making agentic workflows in tools like Codex and Hermes Agent viable without cloud costs — all in a quieter, more compact package.