Question 1

Can I run Llama 3.1 Nemotron Ultra 253B on a Apple M2 Ultra?

Accepted Answer

Yes — Apple M2 Ultra runs Llama 3.1 Nemotron Ultra 253B fully on GPU at the Q4_K_M quantization. Full GPU inference — 192 GB VRAM meets the 164.5 GB recommendation.

Question 2

What quantization of Llama 3.1 Nemotron Ultra 253B should I use on a Apple M2 Ultra?

Accepted Answer

For 192 GB VRAM on the Apple M2 Ultra, the Q4_K_M variant is the best fit. Estimated ~5.1 tokens/sec on the Q4_K_M quantization.

Question 3

How fast does Llama 3.1 Nemotron Ultra 253B run on Apple M2 Ultra?

Accepted Answer

Roughly 5.1 tokens/sec for Q4_K_M. Real speed depends on context length, backend (Ollama, llama.cpp, LM Studio), and KV cache size.

Question 4

What if Apple M2 Ultra is not enough for Llama 3.1 Nemotron Ultra 253B?

Accepted Answer

Try a smaller quantization variant or run on CPU + RAM with the trade-off of slower generation.

Quantization	File Size	Min VRAM	Rec VRAM	Context	Verdict	Estimated tok/s
Q4_K_MBest fit	126.5 GB	145.5 GB	164.5 GB	8K / 8K	Full GPU	~5.1
Q5_K_M	158.1 GB	181.8 GB	205.5 GB	8K / 8K	Partial GPU	~3.1
Q8_0	253 GB	291 GB	328.9 GB	8K / 8K	Can't Run	—
FP16	506 GB	581.9 GB	657.8 GB	8K / 8K	Can't Run	—

Can I Run Llama 3.1 Nemotron Ultra 253B on Apple M2 Ultra?

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Every Llama 3.1 Nemotron Ultra 253B quantization on Apple M2 Ultra