KIEFERSA
Sophea-Titan-1-FP8
FP8_DYNAMIC (W8A8) quantization of Sophea-Titan-1

FP8_DYNAMIC (W8A8) quantization of KIEFERSA/Sophea-Titan-1 — the 27B Greek fine-tuned chat model built on Qwen3.6-27B. Same behaviour as the bf16 release, ≈0.55× the disk / VRAM, and verified lossless (numbers below).

  • Base model: KIEFERSA/Sophea-Titan-1 (bf16)
  • Scheme: FP8_DYNAMIC — per-channel FP8 (E4M3) weights + dynamic per-token FP8 activations (W8A8), compressed-tensors float-quantized
  • Size: 29.4 GB (bf16 base ≈ 54 GB → 0.55×)
  • Creator: Kiefer SA
  • Decoding: non-thinking (enable_thinking=false) — see recommended sampling under Usage

What is / isn't quantized. Data-free one-shot PTQ via llm-compressor (FP8_DYNAMIC, no calibration). Quantized: the language-model Linear layers (attention q/k/v/o, MLP, GDN in/out projections). Kept bf16: lm_head. GDN conv1d/A_log/dt_bias/norms are non-Linear and untouched. This quantized build is text-only — the vision tower of the multimodal base (Sophea-Titan-1) is not included in this FP8 release.

Serve non-thinking. Set enable_thinking=false in the chat template. With thinking left on, Greek output quality degrades.

Verified lossless (this FP8 build)

Measured on this checkpoint through the vLLM decode path (greedy, non-thinking), vs the bf16 base:

Metric bf16 (published) FP8 (this build) Δ
General Greek benchmarks macro (9, logprob) 0.7369 0.7373 +0.0004
English retention macro (5) 0.8783 0.8767 −0.0016
GreekMMLU (30-subj) 0.854 0.853 −0.001

Every axis is within measurement noise of bf16 → lossless. FP8 also loads in HF transformers.

Per-benchmark detail (measured on this FP8 build)

General Greek benchmarks (9, accuracy)

benchmark FP8 bf16
arc_challenge 0.9486 0.950
arc_easy 0.9731 0.973
belebele 0.9511 0.950
greekmmlu 0.8531 0.854
hellaswag 0.6794 0.680
medical_mcqa 0.3912 0.387
truthfulqa 0.4125 0.415
winogrande 0.6290 0.626
mmlu_greek 0.7980 0.797
MACRO 0.7373 0.7369

English retention — 5 benchmarks (accuracy)

benchmark FP8 bf16
arc_challenge 0.9770 0.979
arc_easy 0.9920 0.992
hellaswag 0.8030 0.805
mmlu 0.8554 0.858
winogrande 0.7561 0.758
MACRO 0.8767 0.8783

greekmmlu — per-subject (accuracy)

subject FP8 subject FP8
Accounting 0.859 Greek Traditions 0.886
Agriculture 0.875 Law 0.700
Art 0.753 Management 0.838
Biology 0.868 Maritime Safety & Rescue 0.669
Chemistry 0.802 Mathematics 0.917
Civil Engineering 0.822 Medicine 0.901
Clinical Knowledge 0.820 Modern Greek Language 0.920
Computer Networks & Security 0.762 Physics 0.849
Computer Science 0.880 Prehistory 1.000
Driving Rules 0.821 World History 0.950
Economics 0.922 World Religions 0.774
Education 0.867 Geography 0.964
Electrical Engineering 0.817 Government and Politics 0.932
General Knowledge 0.789 Greek History 0.874
Greek Literature 0.714 Greek Mythology 0.845
OVERALL 0.853

Usage

Serve with vLLM (compressed-tensors FP8 auto-detected; Cutlass FP8 kernels on Blackwell/Hopper):

vllm serve KIEFERSA/Sophea-Titan-1-FP8 --served-model-name sophea-titan-1-fp8 --trust-remote-code \
  --enable-auto-tool-choice --tool-call-parser qwen3_coder \
  --reasoning-parser qwen3

Recommended sampling (instruct / non-thinking): temperature=0.7, top_p=0.80, top_k=20, min_p=0.0, presence_penalty=1.5, repetition_penalty=1.0.

from openai import OpenAI
client = OpenAI(base_url="http://localhost:8000/v1", api_key="EMPTY")
resp = client.chat.completions.create(
    model="sophea-titan-1-fp8",
    messages=[{"role": "user", "content": "Ποια είναι η πρωτεύουσα της Ελλάδας;"}],
    temperature=0,
    extra_body={"chat_template_kwargs": {"enable_thinking": False}},   # required: non-thinking
)
print(resp.choices[0].message.content)

License

Inherits the Qwen3.6-27B base-model license. Verify base-model terms before use.

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