LocalLLMChecker

Unified memory · Apple

What AI models can an Apple M3 Ultra 256GB run?

256 GB is server territory. The constraint stops being memory and becomes bandwidth: everything fits, and what varies is how long you wait for it. Memory is shared with the CPU, so the practical ceiling is lower than the sticker number: macOS hands roughly three quarters of it to the GPU by default.

Memory256 GB
Bandwidth819 GB/s
Usable for a model192 GB
Runtime backendMETAL

The short answer

Assuming an 8k context window and default settings, these are the models worth downloading first.

Best all-rounder

Qwen3.5 122B A10B

Q8_0 · 124.45 GB · about 38.6 tokens/s

Best for code

Qwen3 Coder Next

Q8_0 · 79.4 GB · about 94.9 tokens/s

Largest that still runs well

Qwen3.5 122B A10B

125.09B parameters · Q8_0 · about 38.6 tokens/s

Fastest useful answer

LFM2.5 8B A1B

about 196 tokens/s · 8.78 GB

See how fast it feels

Apple M3 Ultra 256GB running Qwen3.5 122B A10B at Q8_0

Wait for the first word996 ms
Then writes at38.6 tok/s
Whole answer5.5 s

YouWhy does my model use more memory when the conversation gets longer?

Model

Simulated from our estimate at a 512-token question, not a recording. Assumes nothing else is competing for the GPU.

Where it sits

The GPU can use about 192 GB of this machine's 256 GB by default, so for planning it behaves like a 48 GB card with different bandwidth. The 48 GB guide explains what that tier runs and where it runs out, and the bandwidth guide explains why 819 GB/s decides how fast it answers.

Our indicative price for this machine is $5,599 new, reviewed 2026-09-01. That is 4.6 GB of memory and 15 GB/s of bandwidth for every $100. Prices move, so treat these as a place to start a search and not a quote.

Devices in a similar price band, fastest memory first:

DevicePriceMemoryBandwidthBest all-round pick
Apple M2 Ultra 128GB $4,799 128 GB 800 GB/s GPT OSS 120B, 100.1 t/s
Apple M2 Ultra 192GB $6,599 192 GB 800 GB/s Qwen3.5 122B A10B, 37.7 t/s
Apple M4 Max 128GB $4,699 128 GB 546 GB/s GPT OSS 120B, 68.3 t/s
Apple M3 Max 128GB $4,699 128 GB 400 GB/s GPT OSS 120B, 50 t/s

Every model, scored on this device

Each row uses the highest-quality quantization that both fits and stays conversational. Speed is a single-stream estimate at 8k context.

Model Params Verdict Download Memory used Speed Max context
Qwen3.5 122B A10B
Qwen 		125.09B (8.17B active) Runs great Q8_0 124.45 GB 38.6 t/s 256k
GPT OSS 120B
GPT-OSS 		116.83B (5.7B active) Runs great MXFP4 59.65 GB 102.5 t/s 128k
GLM 4.5 Air
GLM 		110.47B (13.4B active) Runs well Q8_0 111.13 GB 22.1 t/s 128k
Qwen3.5 27B
Qwen 		27.78B Runs well Q8_0 28.54 GB 20.7 t/s 256k
Gemma 4 31B Instruct
Gemma 		31.27B Runs well Q8_0 34.64 GB 16.3 t/s 256k
Qwen3 Coder Next
Qwen 		79.67B (3.19B active) Runs great Q8_0 79.4 GB 94.9 t/s 256k
Qwen3 32B
Qwen 		32.76B Runs well Q8_0 34.83 GB 16.5 t/s 32k
Qwen3 Next 80B A3B Instruct
Qwen 		81.32B (3.19B active) Runs great Q8_0 81.04 GB 94.9 t/s 256k
Granite 4.1 30B
Granite 		28.87B Runs well Q8_0 30.94 GB 18.2 t/s 128k
Qwen2.5 32B Instruct
Qwen 		32.76B Runs well Q8_0 34.83 GB 16.5 t/s 32k
Gemma 3 27B Instruct
Gemma 		27.43B Runs well Q8_0 28.65 GB 19.7 t/s 128k
Qwen2.5 Coder 32B Instruct
Qwen 		32.76B Runs well Q8_0 34.83 GB 16.5 t/s 32k
Qwen3.5 35B A3B
Qwen 		35.95B (2.9B active) Runs great Q8_0 36.1 GB 106.1 t/s 256k
Gemma 4 26B A4B Instruct
Gemma 		25.81B (3.74B active) Runs great Q8_0 26.69 GB 71.4 t/s 256k
GLM 4.7 Flash
GLM 		31.22B (3.66B active) Runs great Q8_0 31.61 GB 80.8 t/s 128k
Mixtral 8x7B Instruct V0.1
Mistral 		46.7B (12.88B active) Runs well Q8_0 47.59 GB 23.6 t/s 32k
Llama 3.3 70B Instruct
Llama 		70.55B Runs well Q6_K 56.89 GB 10 t/s 128k
Qwen2.5 72B Instruct
Qwen 		72.71B Runs well Q5_K_M 51.17 GB 11.2 t/s 32k
Qwen2.5 VL 72B Instruct
Qwen 		73.41B Runs well Q5_K_M 51.64 GB 11.1 t/s 64k
Qwen3 30B A3B
Qwen 		30.53B (3.34B active) Runs great Q8_0 31.27 GB 80.3 t/s 32k
Mistral Small 24B Instruct 2501
Mistral 		23.57B Runs well Q8_0 24.98 GB 23.3 t/s 32k
Phi 3.5 MoE Instruct
Phi 		41.87B (6.64B active) Runs great Q8_0 42.81 GB 42.8 t/s 128k
Gemma 4 12B Instruct
Gemma 		11.96B Runs great Q8_0 13.52 GB 42.4 t/s 256k
Qwen3 14B
Qwen 		14.77B Runs great Q8_0 16.28 GB 36.9 t/s 32k
GPT OSS 20B
GPT-OSS 		20.91B (4.18B active) Runs great MXFP4 11.81 GB 135.2 t/s 128k
Qwen3 Coder 30B A3B Instruct
Qwen 		30.53B (3.34B active) Runs great Q8_0 31.27 GB 80.3 t/s 32k
Qwen2.5 14B Instruct
Qwen 		14.77B Runs great Q8_0 16.53 GB 36.3 t/s 32k
Qwen2.5 Coder 14B Instruct
Qwen 		14.77B Runs great Q8_0 16.53 GB 36.3 t/s 32k
Codestral 22B V0.1
Mistral 		22.25B Runs well Q8_0 24.21 GB 23.6 t/s 32k
Qwen3.5 9B
Qwen 		9.65B Runs great Q8_0 10.22 GB 63 t/s 256k
Show the other 56 models
Llama 3 3 Nemotron Super 49B V1 49.87B Runs well Q5_K_M 53.55 GB 10.6 t/s 32k
Phi 4 14.66B Runs great Q8_0 16.48 GB 35.8 t/s 16k
Gemma 3 12B Instruct 12.19B Runs great Q8_0 13.24 GB 43.2 t/s 128k
GLM 5.2 753.33B Fits only at 2 to 3 bits IQ2_XXS 181.79 GB 24.7 t/s 64k
Gemma 4 E4B Instruct 8B Runs great Q8_0 8.39 GB 69.1 t/s 128k
Granite 4.1 8B 8.79B Runs great Q8_0 10.32 GB 56 t/s 128k
Qwen3 8B 8.19B Runs great Q8_0 9.61 GB 64.6 t/s 32k
Mistral Nemo Instruct 2407 12.25B Runs great Q8_0 13.78 GB 43.8 t/s 128k
Qwen2.5 VL 7B Instruct 8.29B Runs great Q8_0 9 GB 68.7 t/s 64k
DeepSeek V3.2 685.4B Fits only at 2 to 3 bits IQ2_XXS 165.38 GB 33 t/s 128k
DeepSeek R1 684.53B Fits only at 2 to 3 bits IQ2_XXS 165.17 GB 33 t/s 128k
Qwen2.5 7B Instruct 7.62B Runs great Q8_0 8.34 GB 74.9 t/s 32k
Llama 3.1 8B Instruct 8.03B Runs great Q8_0 9.32 GB 66.1 t/s 128k
GLM 5.1 753.86B Fits only at 2 to 3 bits IQ2_XXS 181.92 GB 34.8 t/s 64k
DeepSeek Coder V2 Lite Instruct 15.71B Runs great Q8_0 16.09 GB 110.9 t/s 128k
Gemma 2 9B Instruct 9.24B Runs great Q8_0 11.47 GB 50.1 t/s 8k
Qwen2.5 Coder 7B Instruct 7.62B Runs great Q8_0 8.34 GB 74.9 t/s 32k
OLMo 3 7B Instruct 7.3B Runs great Q8_0 10.1 GB 59.8 t/s 64k
Internlm3 8B Instruct 8.8B Runs great Q8_0 9.46 GB 65 t/s 32k
Mistral 7B Instruct V0.3 7.25B Runs great Q8_0 8.55 GB 69.2 t/s 32k
Gemma 4 E2B Instruct 5.12B Runs great Q8_0 5.41 GB 108.8 t/s 128k
Qwen3.5 4B 4.66B Runs great Q8_0 5.24 GB 113.4 t/s 256k
Mistral 7B Instruct V0.2 7.24B Runs great Q8_0 8.54 GB 69.3 t/s 32k
DeepSeek Coder 7B Instruct V1.5 6.91B Runs great Q8_0 10.96 GB 54.7 t/s 4k
DeepSeek Coder 6.7B Instruct 6.74B Runs great Q8_0 11.04 GB 52.8 t/s 16k
LFM2.5 8B A1B 8.47B Runs great Q8_0 8.78 GB 196 t/s 64k
Qwen3 4B 4.02B Runs great Q8_0 5.43 GB 109.1 t/s 32k
Gemma 3 4B Instruct 4.3B Runs great Q8_0 4.88 GB 122.3 t/s 128k
Phi 4 Mini Instruct 3.84B Runs great Q8_0 5.14 GB 116 t/s 128k
Granite 4.1 3B 3.4B Runs great Q8_0 4.31 GB 139.6 t/s 128k
Qwen2.5 3B Instruct 3.09B Runs great Q8_0 3.65 GB 166.8 t/s 32k
Phi 3 Mini 4k Instruct 3.82B Runs great Q8_0 4.87 GB 125.6 t/s 4k
Llama 3.2 3B Instruct 3.21B Runs great Q8_0 4.39 GB 137.4 t/s 128k
LFM2.5 2.6B 2.7B Runs great Q8_0 3.11 GB 199.1 t/s 128k
Qwen3.5 2B 2.27B Runs great Q8_0 2.67 GB 236.1 t/s 256k
Gemma 2 2B Instruct 2.61B Runs great Q8_0 3.51 GB 174.4 t/s 8k
Starcoder2 3B 3.03B Runs great Q8_0 3.46 GB 187.7 t/s 16k
Qwen3 1.7B 2.03B Runs great Q8_0 3.19 GB 193.1 t/s 32k
DeepSeek R1 Distill Qwen 1.5B 1.78B Runs great Q8_0 2.27 GB 318.3 t/s 128k
Qwen2.5 1.5B Instruct 1.54B Runs great Q8_0 2.03 GB 319.5 t/s 32k
SmolLM2 1.7B 1.71B Runs great Q8_0 3.5 GB 174.4 t/s 8k
OLMo 2 0425 1B 1.48B Runs great Q8_0 2.77 GB 246.3 t/s 4k
Llama 3.2 1B Instruct 1.24B Runs great Q8_0 1.79 GB 377 t/s 128k
LFM2.5 1.2B Instruct 1.17B Runs great Q8_0 1.56 GB 497.7 t/s 64k
Gemma 3 1B Instruct 1B Runs great Q8_0 1.32 GB 536 t/s 32k
Qwen3.5 0.8B 0.87B Runs great Q8_0 1.25 GB 572.4 t/s 256k
Qwen3 0.6B 0.75B Runs great Q8_0 1.89 GB 344.3 t/s 32k
Qwen2.5 0.5B Instruct 0.49B Runs great Q8_0 0.85 GB 962.3 t/s 32k
LFM2.5 350M 0.35B Runs great Q8_0 0.71 GB 1490.1 t/s 64k
MiniMax M2.5 228.7B Just fits n/a 228.59 GB 25.3 t/s n/a
MiniMax M2.7 228.69B Just fits n/a 228.58 GB 25.3 t/s n/a
MiniMax M3 427.04B Just fits n/a 212.67 GB 23.6 t/s n/a
GLM 4.5 358.34B Just fits n/a 204.77 GB 14.9 t/s n/a
Qwen3 235B A22B 235.09B Just fits n/a 234.47 GB 13.8 t/s n/a
Kimi K2.6 1026.88B Will not run n/a 578.41 GB n/a n/a
Kimi K2 Instruct 1026.41B Will not run n/a 578.15 GB n/a n/a

What it will not run

7 of the 86 architectures we track are out of reach here, even at 2-bit precision.

Questions people ask about an Apple M3 Ultra 256GB

How much VRAM does an Apple M3 Ultra 256GB have?

The Apple M3 Ultra 256GB has 256 GB of unified memory shared with the CPU, of which roughly 192 GB is available to a model once the operating system takes its share.

Can an Apple M3 Ultra 256GB run a 70B model?

Yes. At Q8_0 a 70B model fits in 79.4 GB and generates around 94.9 tokens per second.

What is the best local model for an Apple M3 Ultra 256GB?

Qwen3.5 122B A10B at Q8_0 is the strongest all-round fit: 124.45 GB used, around 38.6 tokens per second at 8k context.