Nemotron-3-Super-120B-A12B: Sub-second TTFT at 14.4 t/s on DGX Spark (llama.cpp, Q4_K_XL)
If you have been disheartened by 50 second TTFT, maybe we have been making the same mistakes,
or maybe todays (4/2/2026) update brought a welcome improvement. We are approaching usability on
a single DGX Spark for a model designed for agentic approaches. For me, this is a big deal. I have
heard predictions that we should be able to get 30+ tps on this when the inference stack gets
cleaned up a bit.
nVidia: there is this thing called Release Notes. You should try them sometime!
Hardware
- NVIDIA DGX Spark (GB10)
- ARM aarch64 — Cortex-X925 + Cortex-A725 (20 cores)
- 128 GB unified memory
- NVIDIA Driver 580.142 / CUDA 13.0
- Ubuntu, kernel 6.17.0-1014-nvidia
Model
- NVIDIA Nemotron-3-Super-120B-A12B (MoE — 120B total params, 12B active)
- Quantization: Q4_K_XL (GGUF, ~78 GB on disk)
- VRAM usage: ~84 GB
Inference Server
- llama.cpp (build b8398-ee4801e5a)
- Context: 16,384 tokens
- 1 slot, no speculative decoding
Benchmark Results
| Run | Prompt | TTFT | Tokens | TPS |
|---|---|---|---|---|
| 1 | Short (cold) | 1,388 ms | 113 | 14.2 |
| 2 | Short (warm) | 504 ms | 116 | 14.6 |
| 3 | Long output | 814 ms | 1,022 | 14.4 |