I do this for a living — TypeTab ships a 1-billion-parameter model that runs on your Mac and finishes your sentences — so I've spent a lot of time with the question of which model belongs on which machine. Here's the practical map.

Why Macs are unusually good at this

Two words: unified memory. On Apple Silicon, the CPU and GPU share one pool of RAM, so a model that doesn't fit in a PC's video card memory fits fine in a Mac's ordinary memory. Add the Neural Engine and Apple's MLX framework, and a MacBook is the most accessible local-AI machine most people already own.

Apple knows it. The M6 Mac mini starts at $899 and Apple pitches its dual 16-core Neural Engine and memory bandwidth as an AI machine first — I wrote about that in Apple just made the case for local AI. But the pitch works a level down the stack too: the M1 MacBook Air from 2020 runs 7–8B models fine. You don't need new hardware to start today.

What fits where (the honest table)

Model sizes below are parameter counts; the "footprint" is roughly what a 4-bit quantized version needs in memory. Treat these as approximations — quantization varies, and apps add overhead — but they're the right order of magnitude for planning:

Two rules of thumb keep you out of trouble. First, leave breathing room — if a model needs 5GB, don't run it on an 8GB machine that's also running Chrome and Slack; close things or step down a size. Second, bigger isn't automatically better for your actual job — a well-tuned small model beats a generic big one for focused tasks, which is the entire thesis of the product I build.

The tools, in one paragraph each

Ollama — the command line one. ollama run llama3.2 and you're chatting with a local model in your terminal. Free, open source, dead simple, and the de facto standard. If you're a developer, start here.

LM Studio — the GUI one. Search models, download, chat, point local apps at it as an OpenAI-compatible server. Free for personal use. If you're not a terminal person, start here.

Both run the same open models. The choice is interface, not capability. There are others — MLX-native runtimes, llama.cpp directly — but Ollama and LM Studio cover 95% of people reading this.

The honest limits

Local models are not frontier models. A 7–8B model won't match the big cloud models at hard reasoning, long structured documents, or research-shaped tasks. Anyone telling you otherwise is selling something — and I say that as someone who sells local AI.

What local buys you instead:

• Latency. No round trip. Generation starts instantly.
• Privacy. Nothing leaves the machine. Your drafts, your code, your half-finished thoughts never touch a server.
• Cost. No meter. Run it all day.
• Reliability. No rate limits, no outages, no "we've changed your plan."

The right mental model: frontier models for the hard 5% of your thinking, local models for the constant 95% of your typing. That's not a compromise — it's the correct division of labor. I pay for a frontier subscription myself and run local models all day; the two don't compete.

The use case nobody talks about

Here's the thing I'd most like to correct in the "local AI" conversation: the chat window is the least interesting thing you can do with a local model.

A model you talk to occasionally is a toy you show guests. A model that's inside your everyday tools is infrastructure. Local transcription that just works in every meeting. Local search over your own files. And — the one I'm biased about — local autocomplete: a small model, tuned to your writing, that finishes your sentences in every app you type in. That's TypeTab: a 1B model, fine-tuned on your prose on-device, showing up as ghost text in Slack and Mail and your browser. Not a chat window. A layer.

The reason this works — and the reason it can't be a cloud product — is the fine-tuning. The model that finishes your sentences has to learn your vocabulary, and that means training on your actual drafts, which means it has to run where the drafts are. How TypeTab learns your writing style has the mechanism if you're curious.

So yes, download Ollama tonight and chat with a local model — it's genuinely fun and it demystifies the whole thing. But the local-AI payoff for daily work isn't the chat. It's the models you stop noticing.

FAQ

Can a Mac run ChatGPT locally? Not ChatGPT itself — it's a closed cloud service. But open models like Llama, Mistral, and Gemma run locally on any Apple Silicon Mac via Ollama or LM Studio, and cover many everyday uses. For chat-quality reasoning, frontier cloud models still lead; for everyday typing tasks, local models are competitive — and private.

How much RAM do I need to run local LLMs? Roughly: 8GB comfortably runs 7–8B models at 4-bit quantization, 16GB runs 14B, and 70B-class models want 64GB+. Smaller 1–3B models run on any Apple Silicon Mac. Leave headroom for your other apps — a model that barely fits will make the whole machine sluggish.

What's the best tool for running local models on a Mac? Ollama if you're comfortable with the terminal (ollama run llama3.2 and you're going), LM Studio if you want a graphical app with a model browser. Both are free, both run the same open models — the choice is interface, not capability.

Are local models as good as ChatGPT? For hard reasoning and long-form generation, no — frontier cloud models still lead. For latency, privacy, cost, and focused tasks like autocomplete and transcription, local models win outright. The practical setup for most people: a cloud subscription for the hard 5%, local models for the constant 95%.