ⓘ About these figures: speed and score numbers in this guide are LLMCheck index estimates (est.) derived from our published methodology — not lab measurements. Community-verified runs are invited via /contribute.

Why Memory Bandwidth Is Everything

According to the LLMCheck index, LLM inference is memory-bandwidth bound, not compute-bound. Every token generated requires reading the entire model's weights from memory once. The speed at which your Mac can shuttle data from Unified Memory to the GPU determines your tokens-per-second ceiling.

This is why the M5 Max’s 614 GB/s — 12% more than the M4 Max’s 546 GB/s — translates directly into decode speed: about 10–12% faster for the same model, a little less for small ones. The M5 generation’s larger gain is in prompt processing, covered below.

The ceiling: tokens per second cannot exceed memory bandwidth divided by the bytes read per token. Real decode reaches roughly 78% of that on large models, plus a small fixed cost per token — the two-term model behind every LLMCheck estimate.

M5 Family Specs at a Glance

M5 (Base)

  • Memory: 16GB / 24GB / 32GB Unified Memory
  • Bandwidth: 153 GB/s
  • GPU cores: 10, each with a Neural Accelerator
  • Best for: 7–12B models at Q4, Gemma 4 12B, GPT-oss 20B
  • Qwen 3.5 9B (Q4): estimated~23 tok/s

M5 Pro

  • Memory: 24GB / 48GB / 64GB Unified Memory
  • Bandwidth: 307 GB/s
  • GPU cores: 16–20
  • Best for: 30B-class MoE models, 27B dense, 70B dense at 64GB
  • Qwen 3.6-35B-A3B (Q4): estimated~92 tok/s

M5 Max

  • Memory: 36GB / 48GB / 64GB / 128GB Unified Memory
  • Bandwidth: 614 GB/s (460 GB/s on the 32-core GPU)
  • GPU cores: 32–40
  • Best for: the 100B+ MoE tier at 128GB, 70B dense
  • Qwen3.8-Flash-Next (Q4): estimated~49 tok/s

M5 Ultra (Mac Studio, September 2026)

  • Memory: 96GB / 256GB / 512GB Unified Memory
  • Bandwidth: 1,228 GB/s (Apple: 1.2 TB/s)
  • GPU cores: 64–80
  • Best for: 4-bit frontier MoE (MiMo-V2.6-Flash, GLM-5.3-Flash), GLM-5.3 at 512GB
  • Qwen3.8-27B (Q4): sourced~55 tok/s (BGR review)

Estimated Performance: M5 Max vs M4 Max

Corrected 23 September 2026: an earlier version of this section presented a table of M5 Max vs M4 Max results as tests run by LLMCheck, showing gains of about 28%. LLMCheck does not run lab tests, and a 28% decode gain is not consistent with the two chips’ roughly 12% difference in memory bandwidth. The section now gives the index’s estimates, labelled as such.

Token generation on Apple Silicon is bound by memory bandwidth. The M5 Max has about 12% more of it than the M4 Max (614 vs 546 GB/s), so for the same model at the same quantization the LLMCheck index estimates decode roughly 7–12% faster — for example Qwen3.8-27B at ~29 vs ~26 tok/s (estimated, 4-bit). Small models gain slightly less, because a fixed per-token overhead dominates their decode time.

The M5’s larger improvement is in prompt processing, where the new GPU Neural Accelerators do the work: time to first token on long prompts falls far more than decode speed rises. The first independent reviews of the M5 Ultra show the same split — see M5 Ultra and M6, measured. Every figure for both chips is on the benchmarks page, marked with its provenance.

MLX Framework: The M5 Advantage

Apple’s MLX framework is purpose-built for Apple Silicon and it shows: it often decodes about 20% faster than llama.cpp for the same model — one published comparison measured 110 vs 90 tok/s for Qwen 3 30B-A3B on an M4 Max (arXiv 2601.19139).

# Quick MLX benchmark on your M5 Mac
pip install mlx-lm
mlx_lm.generate --model mlx-community/Qwen3.5-30B-A3B-4bit \
  --prompt "Write a function to sort a linked list" \
  --max-tokens 500 --verbose

Neural Accelerators, Not the Neural Engine

The M5 generation’s AI upgrade is in the GPU: every GPU core now has a Neural Accelerator, dedicated matrix hardware. Apple quotes up to 4x faster LLM prompt processing for the M5 Pro and M5 Max than for the M4 Pro and M4 Max.

Model Recommendations per M5 Variant

Based on the LLMCheck index, here is what to run on each M5 chip:

M5 (16–32GB) — Daily Driver Models

M5 Pro (24–64GB) — Power User Models

M5 Max (36–128GB) — Frontier Local AI

M5 Ultra (96–512GB, Mac Studio) — Research Grade

Not sure which M5 variant matches your needs? Use the Best-by-Mac rankings or the Mac Advisor for your exact configuration.

Single-stream decode at 4-bit (DeepSeek V4 Flash at 2-bit) from the LLMCheck index — estimated unless marked; Llama 3.3 70B and Qwen 3.5 9B columns below likewise.

ChipGPU coresBandwidthMax RAMLlama 3.3 70BQwen 3.5 9B
M5 Ultra64–801,228 GB/s512 GBestimated~23 tok/sestimated~146 tok/s
M5 Max32–40614 GB/s128 GBestimated~12 tok/sestimated~82 tok/s
M4 Max32–40546 GB/s128 GBestimated~11 tok/sestimated~74 tok/s
M2 Ultra60–76800 GB/s192 GBestimated~15 tok/sestimated~103 tok/s
M3 Max30–40400 GB/s128 GBestimated~8 tok/sestimated~56 tok/s
M5 Pro16–20307 GB/s64 GBestimated~6 tok/sestimated~44 tok/s
M4 Pro16–20273 GB/s64 GBestimated~5 tok/sestimated~39 tok/s
M3 Pro14–18150 GB/s36 GBDoesn’t fitestimated~22 tok/s