Can Mac Studio M2 Ultra 192GB run Llama-3.1-405B-Instruct?

Apple · 192 GB LPDDR5 · 800 GB/s bandwidth · Meta · 405.9B · model ctx up to 128K

No — Llama-3.1-405B-Instruct at Q4 needs ≈ 264.75 GB even at 4K context, beyond the Mac Studio M2 Ultra 192GB's 192 GB LPDDR5. It would only run with heavy CPU/disk offload. Decode at Q4/8K: ≈ 1.4 tok/s (estimated, batch 1). FP16 needs ≈ 893.8 GB — does not fit on this card. Estimates come from memory-bandwidth math; rows tagged measured override estimates. Relative ranking is more reliable than absolute tok/s. Methodology.

Fit & speed by quant and context

Quant	Context	VRAM needed	Fits?	tok/s (decode)
Q4	4K	264.75 GB	No	1.9 est.
Q4	8K default	305.25 GB	No	1.4 est.
Q4	32K	548.25 GB	No	0.4 est.
FP16	4K	853.3 GB	No	—
FP16	8K default	893.8 GB	No	—
FP16	32K	1136.8 GB	No	—

Fits = weights + KV(ctx) + 1 GB overhead ≤ 95% of VRAM. Measured anchors are context-agnostic; the fit verdict is recomputed per context. A missing tok/s means the model is far beyond this card (offload-only territory).

VRAM breakdown at 8K context

Quant	Weights	KV cache	Overhead	Total needed	Mac Studio M2 Ultra 192GB VRAM
Q4	223.25 GB	81.0 GB	1 GB	305.25 GB	192 GB
FP16	811.8 GB	81.0 GB	1 GB	893.8 GB	192 GB

Other GPUs that run Llama-3.1-405B-Instruct

No catalog GPU fully fits Llama-3.1-405B-Instruct at Q4/8K — see the model page for offload estimates.

All GPUs for Llama-3.1-405B-Instruct →

Other models for the Mac Studio M2 Ultra 192GB

• Qwen3-0.6B — ≈636.4 tok/s Q4 est.
• gemma-3-1b-it — ≈509.1 tok/s Q4 est.
• Llama-3.2-1B-Instruct — ≈424.2 tok/s Q4 est.
• Qwen3-1.7B — ≈254.5 tok/s Q4 est.
• Qwen3-30B-A3B — ≈169.7 tok/s Q4 est.
• Qwen3-Coder-30B-A3B-Instruct — ≈169.7 tok/s Q4 est.
• GLM-4.7-Flash — ≈169.7 tok/s Q4 est.
• Qwen3-30B-A3B-Instruct-2507 — ≈169.7 tok/s Q4 est.

All models on the Mac Studio M2 Ultra 192GB →