On an Apple Silicon Mac with 24GB of unified memory, 172 of 224 catalog builds have good/excellent reference fits at 4K context, and 8 more run with trade-offs. The memory is shared with macOS and your other apps, so the headroom is smaller than the number suggests.
A PC graphics card has its own memory, separate from system RAM. A Mac with Apple Silicon has one pool that the CPU and GPU share. That is why the answer differs from a 24GB graphics card, and why a model never gets the whole 24GB: macOS and open apps use some of it. These pages use a reference scenario. They do not know which M-series chip you have, and Apple sells several chips with the same memory size at very different speeds, so no speed is claimed here.
Four builds to compare by task
Editorial examples chosen for their documented tasks, all Q4_K_M at 4,096 tokens. Check the verdict before downloading. These are estimates, not benchmark rankings.
Model fits within the unified memory GPU allocation.
ollama run qwen2.5:14b
After opening Ollama's prompt, enter /set parameter num_ctx 4096 to match this calculation, within the model's supported maximum. Install a current Ollama release that supports the build. Setup and troubleshooting.
Models that fit — largest memory first — on a 24GB Mac
Showing the 25 largest of 172 models that run well.
How this was calculated
Each model is evaluated at 4K context against 24GB of shared memory on a reference Apple Silicon Mac running the Metal backend, counting weights, KV cache, compute buffers and runtime overhead. The engine reserves memory for macOS and estimates the share available to the GPU. That share is a heuristic. Available memory and current memory pressure are unknown; check Activity Monitor during a real run. Ollama requires macOS 14 or later. See the 16 GB Mac walkthrough for a worked example, or the scan to measure your own Mac.
24GB Mac and local AI — frequently asked questions
Can a Mac with 24GB of memory run local AI models?
172 of the 224 builds evaluated have good/excellent reference fits with 24GB of unified memory at 4K context, and 8 more run with trade-offs. The heaviest that fits is phi4-reasoning:14b, needing about 15.2 GB.
Is unified memory the same as VRAM?
No. On Apple Silicon the 24GB is shared by the CPU, the GPU, macOS and every open app, so a model never gets all of it. The engine reserves room for the system and estimates the share the GPU can use; that share is a heuristic, not a measurement of your Mac.
Does this apply to an Intel Mac?
No. Ollama uses the GPU only on Apple M-series Macs. An Intel Mac runs models on the CPU alone, which is much slower, so do not apply these results to it.