Home / Can I run it? / Mixtral 8x22B / Mixtral 8x22B on a Mac Studio 256GB

Yes, but it is tight. Mixtral 8x22B at Q8_0 needs about 172.8 GB, and the Mac Studio M5 Ultra 256GB has 192.0 GB usable at a ~4k context.

Can I run Mixtral 8x22B on a Mac Studio 256GB?

Mixtral 8x22B at Q8_0 needs about 172.8 GB, and the Mac Studio M5 Ultra 256GB has 192.0 GB usable. That figure is 256 GB of unified memory on the spec sheet, of which 192.0 GB is usable for weights and cache, at 1200 GB/s memory bandwidth. Mixtral 8x22B, a large Mixture-of-Experts. Total weights need a high-memory box; only a fraction is active per token. These are estimates from our formula, not measured benchmarks.

Quant that fits

Q8_0 Fits, short context only

Memory needed

172.8 GB at Q8_0, ~4k context

Usable unified memory

192.0 GB of 256 GB unified memory

Est. tokens/sec

up to 23 estimate

Mixtral-8x22B-Instruct-v0.1 · Mac Studio M5 Ultra 256GB · Everything this machine runs · Q4 vs Q8 vs FP16

Memory at each quant

Estimated tokens per second

Estimate: up to 23 tokens/sec at Q8_0 (upper bound: this is a Mixture-of-Experts, and only the active weights are counted). This is a bandwidth-derived range, not a bench. Efficiency is a 45–80% unified-memory band from How we calculate.

Context headroom

At Q8_0, this machine has headroom out to about 64k tokens under our KV estimate. Longer chats need more memory for the cache. Figures assume an FP16 KV cache.

From the model’s config. Try other sizes in the VRAM calculator or see the context length guide.

What to do instead

• Run gpt-oss-120b instead (82.5 GB at Q4). It is a different model, not a drop-in, but it does fit this machine.
• Keep context short, close other GPU work, and avoid a higher quant. The VRAM calculator shows how the KV cache grows.
• Full hardware list: Mixtral-8x22B-Instruct-v0.1. Specs for this machine: Mac Studio M5 Ultra 256GB.

Other hardware for Mixtral 8x22B

• Mixtral 8x22B on an RTX 4090Won’t fit
• Mixtral 8x22B on an RTX 5090Won’t fit
• Mixtral 8x22B on dual RTX 3090sWon’t fit
• Mixtral 8x22B on a Mac mini 64GBWon’t fit

Other models on a Mac Studio 256GB

• Llama 3.3 70B on a Mac Studio 256GBFits
• R1 Distill 70B on a Mac Studio 256GBFits
• gpt-oss-120b on a Mac Studio 256GBFits
• Qwen3-235B on a Mac Studio 256GBFits
• DeepSeek-R1 on a Mac Studio 256GBWon’t fit
• DeepSeek-V3.2 on a Mac Studio 256GBWon’t fit