M4 Max 128GB vs AMD RX 7900 XTX for local LLMs
52 reports on the M4 Max 128GB and 46 on the AMD RX 7900 XTX
Which is faster for local LLMs?
On Qwen3.8 27B at 4-bit, the M4 Max 128GB has 21.8 generation tokens/s (one run); prompt processing 236.6 tokens/s (one run); the AMD RX 7900 XTX has 42.5 generation tokens/s (6 runs); prompt processing 640.0 tokens/s (4 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 1.8x higher on the AMD RX 7900 XTX (546 GB/s on the M4 Max 128GB, 960 on the AMD RX 7900 XTX). Across 3 shared models with generation measurements on both cards, the M4 Max 128GB's median is higher on 0 and the AMD RX 7900 XTX's on 3.
- Memory
- 128GB unified
- Memory bandwidth
- 546 GB/s
- FP16 compute
- 18.4 TFLOPS
- Reports
- 52
- Memory
- 24GB
- Memory bandwidth
- 960 GB/s
- FP16 compute
- 123 TFLOPS
- Reports
- 46
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 | AMD RX 7900 XTX |
|---|---|---|
| Qwen3.8 27B4-bit | 21.8one runPP 236.6 (one run)llama.cppcontext not stated | 42.56 runsPP 640.0 (4 runs)llama.cpp, Ollama, 2 not stated64K to 220K context, 3 not stated |
| Gemma 4 26B · 4B active4-bit | 88.1one runPP 1408.1 (one run)llama.cppcontext not stated | 142.8one runPP 4331.2 (one run)llama.cppcontext not stated |
| Qwen3.6 35B · 3B active4-bit | 81.1one runPP 1423.5 (one run)llama.cppcontext not stated | 125.5one runPP 1874.7 (one run)llama.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 | AMD RX 7900 XTX |
|---|---|---|
| Qwen3.8 27B | 6.7 t/sFP16 | 34.8 t/sQ4_K_M |
| Gemma 4 26B · 4B active | 18.2 t/sFP16 | 78.4 t/sQ5_K_S |
| Qwen3.6 35B · 3B active | 21.2 t/sFP16 | 123.2 t/sQ4_K_S |
| Qwen3.8 125B · 6B active | 30.7 t/sQ5_K_S | 19.5 t/sQ2_K, experts in RAM |
| DeepSeek V4 Flash 284B · 13B active | 48.3 t/sQ2_K | doesn't fit at these settings |
| Qwen3.6 27B | 6.7 t/sFP16 | 34.8 t/sQ4_K_M |
| DeepSeek V4.1 Flash 552B · 16B active | doesn't fit at these settings | doesn't fit at these settings |
| GLM-5.3 320B · 18B active | doesn't fit at these settings | doesn't fit at these settings |
| Qwen3.5 9B | 20.2 t/sFP16 | 58.7 t/sQ8_0 |
Change the context, RAM or model in the calculator: M4 Max 128GB · AMD RX 7900 XTX
Every report on each card, with its source: M4 Max 128GB · AMD RX 7900 XTX