llamaperf

M4 24GB vs AMD RX 7900 XTX for local LLMs

8 reports on the M4 24GB and 46 on the AMD RX 7900 XTX

Which is faster for local LLMs?

On Qwen3.8 27B at 4-bit, the M4 24GB has 6.5 generation tokens/s (one run); prompt processing 60.8 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 8.0x higher on the AMD RX 7900 XTX (120 GB/s on the M4 24GB, 960 on the AMD RX 7900 XTX).

M4 24GB
Memory
24GB unified
Memory bandwidth
120 GB/s
FP16 compute
4.3 TFLOPS
Reports
8
AMD RX 7900 XTX
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

ModelM4 24GBAMD RX 7900 XTX
Qwen3.8 27B4-bit6.5one runPP 60.8 (one run)llama.cppcontext not stated42.56 runsPP 640.0 (4 runs)llama.cpp, Ollama, 2 not stated64K to 220K context, 3 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.

ModelM4 24GBAMD RX 7900 XTX
Qwen3.8 27B10.8 t/sQ2_K34.8 t/sQ4_K_M
Qwen3.8 125B · 6B activedoesn't fit at these settings19.5 t/sQ2_K, experts in RAM
Qwen3.6 35B · 3B active35.8 t/sQ2_K123.2 t/sQ4_K_S
DeepSeek V4 Flash 284B · 13B activedoesn't fit at these settingsdoesn't fit at these settings
Qwen3.6 27B10.8 t/sQ2_K34.8 t/sQ4_K_M
Gemma 4 26B · 4B active24.1 t/sQ3_K_S78.4 t/sQ5_K_S
DeepSeek V4.1 Flash 552B · 16B activedoesn't fit at these settingsdoesn't fit at these settings

Change the context, RAM or model in the calculator: M4 24GB · AMD RX 7900 XTX

Every report on each card, with its source: M4 24GB · AMD RX 7900 XTX

More comparisons