llmrun

Apple · M2 Ultra · Desktop

Best AI Models for Mac Pro M2 Ultra (128 GB)

Runs 27–31B and 120B MoE models well; dense 70B fits but is slow at 12 tok/s.

128 GB unified124.5 GB for models800 GB/s54 TFLOPS FP162023

Top models by task

#ModelSpeedCoding ScoreQuant · Memory
1
Q4_K_M · 17.9 GB
32.1 tok/sQ4_K_M · 17.9 GB
2
Q4_K_M · 21.7 GB
27.5 tok/sQ4_K_M · 21.7 GB
3
Q4_K_M · 22.0 GB
75.9 tok/sQ4_K_M · 22.0 GB
4
Q4_K_M · 16.5 GB
91.7 tok/sQ4_K_M · 16.5 GB
5
Q4_K_M · 19.3 GB
77.0 tok/sQ4_K_M · 19.3 GB
See all 367 models on the Mac Pro M2 Ultra →Bars = traction for models without a Score yet
Task rankings use that task's benchmarks, topped up from Overall when short; bars mark well-known models with no Score yet.

About the Mac Pro M2 Ultra (128 GB)

The Mac Pro M2 Ultra is the fastest 128 GB machine: it runs 27–31B and 120B MoE models well. macOS keeps about 3.5 GB, leaving 124.5 GB for models. Prompt reading is its weak spot: a 4K-token prompt waits 21 s before the first word on Qwen3.8 27B. M2 Ultra generation, released 2023; the newer M3 Ultra writes 1% faster with 0.8× the compute.

Speed in 128 GB#1800 GB/s
Prompt reading#454 TFLOPS
For models124.5 GBmacOS keeps 3.5 GB
ChipM2 Ultrareleased 2023

Mac Pro M2 Ultra strengths and weaknesses

Strengths

  • Runs 120B MoE models: GPT OSS 120B at 74.6 tok/s in 70.8 GB
  • Room for long context: Qwen3.8 27B at Q4 uses 17.9 GB, leaving 106.6 GB free

Weaknesses

  • Slow prompt reading: A 32K-token prompt on Qwen3.8 27B waits 2.8 min for the first token
  • No CUDA: vLLM, AWQ, GPTQ and FP8 builds don't run; use GGUF or MLX

Memory for models

124.5 GB of 128 GB
35B MoE22 GB70B51.3 GB123B74.7 GB
35B MoE22 GB123B74.7 GB
For models 124.5 GBmacOS keeps 3.5 GBModel size at Q4

Everything on the size ladder fits. Two 27B-class models together use 35.7 GB and leave 88.8 GB free.

Similar devices and alternatives

Other memory sizes of the same machine first, then machines and GPUs people weigh against it, each with the one reason it is worth a look. Speeds on Qwen3.6 35B A3B.

Mac Pro M2 Ultra tokens per second by model size

Output speed depends on memory bandwidth (800 GB/s). Grey rows need more than the 124.5 GB available.

  1. 9BQwen3.5 9B · Q4_K_M · 6.6 GB
    88.1tok/s
  2. 14BQwen3 14B · Q4_K_M · 11.9 GB
    58.9tok/s
  3. 27–31BQwen3.8 27B · Q4_K_M · 17.9 GB
    32.1tok/s
  4. 35B MoEQwen3.6 35B A3B · Q4_K_M · 22.0 GB
    75.9tok/s
  5. 70BLlama 3.3 70B Instruct · Q4_K_M · 51.3 GB
    12.0tok/s
  6. 120B MoEGPT OSS 120B · Q4_K_M · 70.8 GB
    74.6tok/s

Estimated speeds: Q4_K_M, 4K context, one user. How we estimate

Ultra generations: writing vs compute

M1 Ultra → M3 Ultra
Writing speed (tok/s)Compute (TFLOPS FP16)
1×2×3×M1 Ultra2022M2 Ultra2023M3 Ultra2025M1 Ultra · 31.2 TFLOPS FP16M1 Ultra · 75.9 tok/s · 800 GB/sM2 Ultra · 54.4 TFLOPS FP16M2 Ultra · 75.9 tok/s · 800 GB/sM3 Ultra · 43 TFLOPS FP16M3 Ultra · 76.6 tok/s · 819 GB/sCompute 1.4×Writing +1%
1×2×3×M12022M22023M32025M1 Ultra · 31.2 TFLOPS FP16M1 Ultra · 75.9 tok/s · 800 GB/sM2 Ultra · 54.4 TFLOPS FP16M2 Ultra · 75.9 tok/s · 800 GB/sM3 Ultra · 43 TFLOPS FP16M3 Ultra · 76.6 tok/s · 819 GB/sCompute 1.4×Writing +1%

Writing speed follows memory bandwidth and barely moved: 75.9 to 76.6 tok/s since the M1 Ultra. Compute, which sets how fast prompts are read, grew 1.4×. Indexed to the M1 Ultra; speeds on Qwen3.6 35B A3B, same 128 GB.

All 367 models on the Mac Pro M2 Ultra

Featured only

Best quant that fits in 124.5 GB, ordered by llmrun Score. Fit grades how well it runs here, S best. How ranking works

LLM models compatible with Mac Pro M2 Ultra (128 GB) — ranked by Score, recency and Fit
ModelVRAMScoreFit
Qwen3.8 27B
27.8B·Q4_K_M·32.1 t/s·262K ctx
17.9 GBA71, Runs well
Gemma 4 26B A4B IT
25.8B·Q4_K_M·91.7 t/s·262K ctx
16.5 GBS90, Runs great
Muse Glimmer 30B
29.8B·Q4_K_M·30.5 t/s·131K ctx
19.6 GBA71, Runs well
Gemma 4 31B IT
31.3B·Q4_K_M·27.5 t/s·262K ctx
21.7 GBA68, Runs well
31.6B·Q4_K_M·77.0 t/s·262K ctx
19.3 GBS87, Runs great
GLM 4.7 Flash
31.2B·Q4_K_M·68.4 t/s·203K ctx
19.9 GBS85, Runs great
Inkling Small
266.0B·IQ3_S·103.0 t/s
116.2 GBB62, Decent
Qwen3.6 35B A3B
36.0B·Q4_K_M·75.9 t/s·262K ctx
22.0 GBS87, Runs great
JEV 27B VL
27.8B·Q4_K_M·32.1 t/s·262K ctx
17.9 GBA71, Runs well
GPT OSS 120B
116.8B·Q4_K_M·74.6 t/s·131K ctx
70.8 GBS86, Runs great
123.6B·Q4_K_M·31.6 t/s·262K ctx
74.7 GBA71, Runs well
Qwen3.5 9B
9.7B·Q4_K_M·88.1 t/s·262K ctx
6.6 GBS89, Runs great
Ling 3.0 Flash
127.5B·Q4_K_M·69.0 t/s·262K ctx
77.6 GBS86, Runs great
MiMo V2.6 Distill Qwen 9B
9.4B·Q4_K_M·90.2 t/s·262K ctx
6.5 GBS90, Runs great
Qwen3.8 Flash Next
180.0B·Q4_K_M·13.2 t/s·262K ctx
109.0 GBC41, Usable

Mac Pro M2 Ultra specs

Specs

Chip
M2 Ultra
CPU cores
24
GPU cores
76
Unified memory
128 GB
For models
124.5 GB (macOS keeps 3.5 GB)
Memory bandwidth
800 GB/s
FP16 (dense)
54.4 TFLOPS
Neural Engine
32 TOPS
Released
2023-06-13

Mac Pro M2 Ultra FAQ

How much memory is available for AI on the Mac Pro M2 Ultra (128 GB)?

About 124.5 GB of the 128 GB. macOS keeps roughly 3.5 GB for itself and other apps.

What is the largest model the Mac Pro M2 Ultra (128 GB) can run?

NVIDIA Nemotron 3 Super 120B A12B BF16 (123.6B) at Q4_K_M uses 74.7 GB, 60% of the available memory, and runs at about 31.6 tok/s.

How long does the Mac Pro M2 Ultra (128 GB) take to read a long prompt?

On Qwen3.8 27B, about 21 s for a 4K-token prompt and 2.8 min for a 32K-token document before the first word appears.

Is renting a GPU cheaper than buying the Mac Pro M2 Ultra?

An A100 (80 GB) rents from $1.10/hr.