M5 Ultra 512GB vs AMD Strix Halo 128GB for local LLMs
1 report on the M5 Ultra 512GB and 320 on the AMD Strix Halo 128GB
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 4.8x higher on the M5 Ultra 512GB (1,229 GB/s on the M5 Ultra 512GB, 256 on the AMD Strix Halo 128GB). The estimates below compare them on the models people run most.
M5 Ultra 512GB
- Memory
- 512GB unified
- Memory bandwidth
- 1,229 GB/s
- FP16 compute
- not on record
- Reports
- 1
AMD Strix Halo 128GB
- Memory
- 128GB unified
- Memory bandwidth
- 256 GB/s
- FP16 compute
- 59 TFLOPS
- Reports
- 320
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 | M5 Ultra 512GB | AMD Strix Halo 128GB |
|---|---|---|
| Qwen3.8 27B | 14.9 t/sFP16 | 3.5 t/sFP16 |
| Qwen3.8 125B · 6B active | 25.4 t/sFP16 | 12.6 t/sQ6_K |
| Qwen3.6 35B · 3B active | 53.5 t/sFP16 | 12.6 t/sFP16 |
| DeepSeek V4 Flash 284B · 13B active | 42.1 t/sQ8_0 | 33.5 t/sQ2_K |
| Qwen3.6 27B | 14.9 t/sFP16 | 3.5 t/sFP16 |
| Gemma 4 26B · 4B active | 40.1 t/sFP16 | 9.5 t/sFP16 |
Change the context, RAM or model in the calculator: M5 Ultra 512GB · AMD Strix Halo 128GB
Every report on each card, with its source: M5 Ultra 512GB · AMD Strix Halo 128GB