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Apple M3 Ultra (512GB)

The Apple M3 Ultra (512GB) uses a unified memory architecture. For reliable local LLM inference without OS memory pressure, this benchmark models a 75% usable allocation (384 GB) with 819 GB/s unified memory bandwidth.

Memory

512 GB

Usable Memory Ceiling

384 GB (75% usable budget)

Bandwidth

819.2 GB/s

Max Inference Class

70B+ Models (Q4)

TDP

250W

VRAM Scaling by Context Length

Estimated memory requirements as context length increases. Curves crossing above the reference line indicate Out of Memory (OOM).

DeepSeek-R1 14B (14B)Qwen3-32B (32B)Step 3.5 Flash (196.81B (11B active))MiMo V2.6 Pro RL (1020B (42B active))

Precision:

Best Models to Run on Apple M3 Ultra (512GB)

Inference throughput, memory compatibility, and generation speeds for open-weights LLMs on Apple M3 Ultra (512GB).

Sort by:

Context:

KV Cache:

RankModelParametersPrecisionTPS (Approx.)TTFTCan Run

#14

DeepSeek V4.1 Flash

552B (16B active)

INT4

63 tok/s

~10.0s

#15

GLM-5.3

753.9B (51.6B active)

INT4

21 tok/s

~20.5s

#25

GLM-5.2

744B (40B active)

INT4

26 tok/s

~15.9s

#30

DeepSeek-V4-Flash-Vision-Exp

290.9B (20.4B active)

INT4
Q8

52 tok/s

31 tok/s

~6.9s

~6.9s

#31

Hunyuan 4 Preview

770B (49B active)

INT4

22 tok/s

~19.5s

#42

Qwen 3.8 Flash

176B (6B active)

INT4
Q8
FP16

123 tok/s

83 tok/s

46 tok/s

~2.1s

~2.1s

~2.2s

#44

MiMo-V2.6-Flash

309B

INT4
Q8

4 tok/s

2 tok/s

~107.0s

~116.5s

#48

Qwen 3.8 27B

27B

INT4
Q8
FP16

39 tok/s

23 tok/s

12 tok/s

~9.5s

~9.6s

~9.6s

#49

Hunyuan 4 Preview

770B (49B active)

INT4

22 tok/s

~19.5s

#54

Qwen3.5-397B-A17B

397B (17B active)

INT4
Q8

40 tok/s

26 tok/s

~9.3s

~10.9s

#55

GLM-5.1

754B (40B active)

INT4

25 tok/s

~22.1s

#57

GLM-4.5

355B (32B active)

INT4
Q8

11 tok/s

9 tok/s

~14.1s

~16.6s

#58

DeepSeek-V4-Flash

284B (13B active)

INT4
Q8

74 tok/s

45 tok/s

~4.4s

~4.4s

#59

Qwen3 235B A22B Thinking

235B (22B active)

INT4
Q8

16 tok/s

14 tok/s

~9.6s

~9.6s

#71

MiniMax M3.1 Flash

428B (23B active)

INT4

47 tok/s

~7.8s

#72

Sarvam-105B

106B (10.3B active)

INT4
Q8
FP16

83 tok/s

53 tok/s

30 tok/s

~4.9s

~4.9s

~4.9s

#74

GLM-5.3 Flash

313.3B (17.3B active)

INT4
Q8

59 tok/s

34 tok/s

~5.9s

~6.4s

#77

K2 Horizon 375B A23B

375B (23B active)

INT4
Q8

34 tok/s

21 tok/s

~11.1s

~13.1s

#83

K2 Horizon MoVA 36B A4B

36B (4B active)

INT4
Q8
FP16

131 tok/s

99 tok/s

63 tok/s

~1.9s

~1.9s

~1.9s

#84

GLM-4.7

358B (32B active)

INT4
Q8

11 tok/s

9 tok/s

~14.1s

~16.6s

Inference Capacity

Maximum model parameter class runnable by weight precision.

Context:

4-bit

Q4

70B+ Models

8-bit

Q8

70B Models

16-bit

FP16

70B Models

Fine-Tuning Capacity

Hardware capacity for local training and adapter fine-tuning.

Context Length:

QLoRA

4-bit

70B+ Models

LoRA

16-bit

70B Models

Full Parameter Training

7B-8B Models

Workload Recommendations

Guidance for optimal precision and operational ceilings on Apple M3 Ultra (512GB).

Inference Sweet Spot

Suitable for 70B parameter models at Q4/Q8 with extended 32k context windows, or high-throughput batching of smaller dense architectures.

Bandwidth & Speed Profile

With 819.2 GB/s aggregate bandwidth, batch size 1 inference operates in a memory-bandwidth bound regime. Generates approximately 182 tok/s on an 8B Q4 model and 22 tok/s on a 70B Q4 model.

Unified Memory Budget

Modeled with a 75% usable allocation budget to preserve system RAM for macOS and display compositor processes.

Frequently Asked Questions