M4 Max 128GB vs M4 Max 48GB for local LLMs
52 reports on the M4 Max 128GB and 1 on the M4 Max 48GB
Which is faster for local LLMs?
On Qwen3.5 4B at 4-bit, the M4 Max 128GB has 101.4 generation tokens/s (one run); prompt processing 1476.8 tokens/s (one run); the M4 Max 48GB has 85.0 generation tokens/s (one run). 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 about the same on both (546 GB/s on the M4 Max 128GB, 546 on the M4 Max 48GB).
- Memory
- 128GB unified
- Memory bandwidth
- 546 GB/s
- FP16 compute
- 18.4 TFLOPS
- Reports
- 52
- Memory
- 48GB unified
- Memory bandwidth
- 546 GB/s
- FP16 compute
- 18.4 TFLOPS
- Reports
- 1
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
| Model | M4 Max 128GB | M4 Max 48GB |
|---|---|---|
| Qwen3.5 4B4-bit | 101.4one runPP 1476.8 (one run)llama.cppcontext not stated | 85.0one runllama.cppcontext 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.
| Model | M4 Max 128GB | M4 Max 48GB |
|---|---|---|
| Qwen3.5 4B | 45.5 t/sFP16 | 45.5 t/sFP16 |
| Qwen3.8 27B | 6.7 t/sFP16 | 16.6 t/sQ6_K |
| Qwen3.8 125B · 6B active | 30.7 t/sQ5_K_S | doesn't fit at these settings |
| Qwen3.6 35B · 3B active | 21.2 t/sFP16 | 66.0 t/sQ5_K_M |
| DeepSeek V4 Flash 284B · 13B active | 48.3 t/sQ2_K | doesn't fit at these settings |
| Qwen3.6 27B | 6.7 t/sFP16 | 16.6 t/sQ6_K |
| Gemma 4 26B · 4B active | 18.2 t/sFP16 | 32.3 t/sQ8_0 |
Change the context, RAM or model in the calculator: M4 Max 128GB · M4 Max 48GB
Every report on each card, with its source: M4 Max 128GB · M4 Max 48GB