The best local LLM for a Mac Studio M5 Ultra (512 GB) is Qwen3.8-Flash-Next at 84 tok/s (estimated). With 512 GB of unified memory it runs 71 of the models in the LLMCheck index — from compact options up to 753B-class models. For everyday chat and coding, Qwen3.8-Flash-Next is the sweet spot. Full ranking below.
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Mac Studio M5 Ultra (512GB) on Amazon → · not sure? the Mac Advisor picks a config →
Ranked by LLMCheck suitability (capability balanced against speed on the M5 Ultra). Click a model for its full benchmark and setup. Every speed carries its provenance mark: most are index estimates from the memory-bandwidth model, and a filled square is a published measurement — submit a real run →
| # | Model | Size | License | Speed | Capability |
|---|---|---|---|---|---|
| 1 | Qwen3.8-Flash-Next | 125B | Qwen Custom | estimated84 tok/s | 47/50 |
| 2 | MiMo-V2.6-Flash | 309B | MIT | estimated42 tok/s | 49/50 |
| 3 | KAT-Coder-V2.5 | 35B | Apache 2.0 | estimated148 tok/s | 39/50 |
| 4 | Qwen 3.6-35B-A3B | 35B | Apache 2.0 | estimated155 tok/s | 38/50 |
| 5 | GLM 5.2 | 753B | MIT | estimated22 tok/s | 50/50 |
| 6 | Qwen3.8-27B | 27.8B | Apache 2.0 | sourced55 tok/s | 46/50 |
| 7 | DeepSeek V4 Flash Vision-Exp | 305B | MIT | estimated46 tok/s | 47/50 |
| 8 | DeepSeek V4 Flash | 284B | MIT | estimated45 tok/s | 47/50 |
| 9 | GLM-5.3-Flash | 320B | MIT | estimated35 tok/s | 48/50 |
| 10 | GLM-5.3 | 753B | GLM-5.3 | estimated17 tok/s | 50/50 |
| 11 | Inkling-Small | 276B | Apache 2.0 | estimated49 tok/s | 46/50 |
| 12 | Laguna S 2.1 | 118B | OpenMDW | estimated68 tok/s | 43/50 |
Showing the top 12 of 71 models that fit in 512 GB. See the full leaderboard or all benchmarks.
The fastest way to get started is Ollama. Install it, then find the top pick for your Mac in its library and copy the exact tag it lists:
Find Qwen3.8-Flash-Next in the Ollama library → · model card on Hugging Face →
Prefer a GUI? LM Studio gives you a one-click download and chat window. For step-by-step help see our Ollama install guide, or open the Qwen3.8-Flash-Next on M5 Ultra benchmark page for exact settings.
The Mac Studio M5 Ultra (512 GB) comfortably runs 71 of the models in the LLMCheck index, led by Qwen3.8-Flash-Next. Grab one and start running LLMs offline today:
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Qwen3.8-Flash-Next (125B, Qwen Custom) is the best all-round pick at 84 tok/s (estimated) on the M5 Ultra. If you want maximum speed, Maple Preview 20B-A1B hits 503 tok/s (estimated); for maximum capability, GLM 5.2 still fits in 512 GB.
About 71 of the 91 models in the LLMCheck leaderboard fit in 512 GB of unified memory, from compact models up to GLM 5.2 (753B).
Yes. A 70B model in Q4 quantization needs roughly 40–44 GB of memory, which fits in 512 GB with headroom for context.
512 GB is plenty for local AI — you can run capable 30B–70B-class models. Because Apple Silicon uses unified memory, that figure is both your system RAM and your VRAM.