llamaperf

M3 Pro 18GB vs M5 Max 48GB for local LLMs

1 report on the M3 Pro 18GB and 66 on the M5 Max 48GB

Which is faster for local LLMs?

On Qwen3 8B at 4-bit, the M3 Pro 18GB has 25.2 generation tokens/s (one run); the M5 Max 48GB has 104.2 generation tokens/s (2 runs); prompt processing 2947.6 tokens/s (2 runs). Those are community reports whose engines and settings differ, so the gap is a rough sign, not a controlled measure of the two cards. Memory bandwidth, which caps how fast a card can write, is 4.0x higher on the M5 Max 48GB (154 GB/s on the M3 Pro 18GB, 614 on the M5 Max 48GB).

M3 Pro 18GB
Memory
18GB unified
Memory bandwidth
154 GB/s
FP16 compute
7.4 TFLOPS
Reports
1
M5 Max 48GB
Memory
48GB unified
Memory bandwidth
614 GB/s
FP16 compute
not on record
Reports
66

Measured on both

Generation and prompt processing speeds from plain runs (one device, one request, no speculative decoding, the whole model in the device's memory) of the same model size at the same bit class. Each side shows the engines and reported context behind its median. Context can mean a configured window or prompt depth, so these are community comparisons with differing settings. How to read these

ModelM3 Pro 18GBM5 Max 48GB
Qwen3 8B4-bit25.2one runllama.cpp1K context104.22 runsPP 2947.6 (2 runs)llama.cpp, MLXcontext not stated

Estimated by the calculator

The quant the calculator recommends for each card and its estimated speed at a 32,768-token context with 32 GB of system RAM, from memory bandwidth and the model's shape. Where a model was also measured above, the measurement wins.

ModelM3 Pro 18GBM5 Max 48GB
Qwen3 8B33.8 t/sQ3_K_M30.5 t/sFP16
Qwen3.8 27Bdoesn't fit at these settings22.3 t/sQ6_K
Qwen3.8 125B · 6B activedoesn't fit at these settingsdoesn't fit at these settings
Qwen3.6 35B · 3B activedoesn't fit at these settings88.4 t/sQ5_K_M
DeepSeek V4 Flash 284B · 13B activedoesn't fit at these settingsdoesn't fit at these settings
Qwen3.6 27Bdoesn't fit at these settings22.3 t/sQ6_K
Gemma 4 26B · 4B active35.1 t/sQ2_K43.2 t/sQ8_0

Change the context, RAM or model in the calculator: M3 Pro 18GB · M5 Max 48GB

Every report on each card, with its source: M3 Pro 18GB · M5 Max 48GB

More comparisons