Practical Warning
- Not a serious instruction model
- Not reliable for Japanese reasoning
- Not reliable for arithmetic, logic, coding, or factual answers
- Useful only for testing NVFP4 loading, serving, KV-cache behavior, and raw TPS
Quantization
- Source precision: BF16 safetensors
- Output format:
compressed-tensors
- NVFP4 format:
nvfp4-pack-quantized
- Scheme:
NVFP4 W4A4
- Targets:
Linear
- Ignored modules:
lm_head
- Calibration:
neuralmagic/calibration, LLM, 512 samples, max sequence 4096
- Tooling:
llmcompressor, compressed-tensors
The resulting model.safetensors is about 2.82 GB.
vLLM Usage
For a 128K context run with FP8 KV cache:
vllm serve sakamakismile/fable-traces-NVFP4 \ --max-model-len 131072 \ --kv-cache-dtype fp8 \ --gpu-memory-utilization 0.92
For Python:
from vllm import LLM, SamplingParams llm = LLM( model="sakamakismile/fable-traces-NVFP4", max_model_len=131072, kv_cache_dtype="fp8", gpu_memory_utilization=0.92,) messages = [[{"role": "user", "content": "Tell me something interesting."}]]outputs = llm.chat(messages, SamplingParams(max_tokens=128, temperature=0.0))print(outputs[0].outputs[0].text)
Benchmark
Measured locally with vLLM 0.21.0+cu129 on NVIDIA RTX PRO 2000 Blackwell
16 GB GPUs, driver 595.71.05.
Common settings:
max_model_len=131072
kv_cache_dtype=fp8
max_num_seqs=8
max_tokens=256
repeats=3, warmup=1
enforce_eager=True
TP=1
vLLM reported 156,576 GPU KV-cache tokens with FP8 KV cache.
Table with columns: TP, Parallel, Mean output tok/s, Best output tok/s, Mean total tok/s| TP | Parallel | Mean output tok/s | Best output tok/s | Mean total tok/s |
|---|
| 1 | 1 | 69.03 | 71.45 | 118.07 |
| 1 | 2 | 129.30 | 131.40 | 219.80 |
| 1 | 4 | 238.04 | 244.81 | 404.32 |
| 1 |
TP=2
vLLM reported 359,488 GPU KV-cache tokens with FP8 KV cache.
Table with columns: TP, Parallel, Mean output tok/s, Best output tok/s, Mean total tok/s| TP | Parallel | Mean output tok/s | Best output tok/s | Mean total tok/s |
|---|
| 2 | 1 | 60.37 | 60.72 | 103.26 |
| 2 | 2 | 100.86 | 122.85 | 166.75 |
| 2 | 4 | 234.43 | 236.21 | 388.02 |
| 2 |
For this short-output benchmark, TP=1 is faster; TP=2 mainly buys more KV-cache
headroom for long-context use.
Raw benchmark files are included under benchmarks/.