M3 Pro 18GB vs NVIDIA RTX 3090 for local LLMs
1 report on the M3 Pro 18GB and 219 on the NVIDIA RTX 3090
Which is faster for local LLMs?
Nobody has reported the same model at the same quant on both cards yet, so there's no measured head-to-head. Memory bandwidth, which caps how fast a card can write, is 6.1x higher on the NVIDIA RTX 3090 (154 GB/s on the M3 Pro 18GB, 936 on the NVIDIA RTX 3090). The estimates below compare them on the models people run most.
M3 Pro 18GB
- Memory
- 18GB unified
- Memory bandwidth
- 154 GB/s
- FP16 compute
- 7.4 TFLOPS
- Reports
- 1
NVIDIA RTX 3090
- Memory
- 24GB
- Memory bandwidth
- 936 GB/s
- FP16 compute
- 142 TFLOPS
- Reports
- 219
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.
| Model | M3 Pro 18GB | NVIDIA RTX 3090 |
|---|---|---|
| Qwen3.8 27B | doesn't fit at these settings | 33.9 t/sQ4_K_M |
| Qwen3.8 125B · 6B active | doesn't fit at these settings | 19.4 t/sQ2_K, experts in RAM |
| Qwen3.6 35B · 3B active | doesn't fit at these settings | 120.1 t/sQ4_K_S |
| DeepSeek V4 Flash 284B · 13B active | doesn't fit at these settings | doesn't fit at these settings |
| Qwen3.6 27B | doesn't fit at these settings | 33.9 t/sQ4_K_M |
| Gemma 4 26B · 4B active | 35.1 t/sQ2_K | 76.4 t/sQ5_K_S |
Change the context, RAM or model in the calculator: M3 Pro 18GB · NVIDIA RTX 3090
Every report on each card, with its source: M3 Pro 18GB · NVIDIA RTX 3090