AI & ML interests

KV cache compression, inference optimization, model compression

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samuel-salfati  updated a model 5 days ago
fraQtl/Qwen3.5-4B-NPU-GGUF
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samuel-salfati  updated a collection 6 days ago
KV cache · more users per GPU
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Organization Card

fraQtl. On device: Qwen3.5-4B 37.8% closer to the original on task text than the stock unsloth Q4_0, at fewer bytes, same speed on the Snapdragon NPU. On servers: 17 users at 128K on one H100 where FP8 KV fits 9.

new: Qwen3.5-4B NPU GGUF website: fraqtl.ai paper: arXiv 2604.11501 pip: fraqtl-diagnostic

Model families: Qwen · Gemma 4 · Llama · Mistral · LFM2: dense, mixture-of-experts and hybrid, 1B to 35B

Browse: NPU-native GGUF · Hi-Fi GGUF · KV cache for servers

Every number below is measured on the exact file we publish, against the strongest public file at the same size or larger, with the receipts in the repo.


▚ On device: GGUF files for phones, laptops and NPUs

Qwen3.5-4B on device: fraQtl Q4_0 is 37.8% closer to the original on task text than unsloth Q4_0, at fewer bytes, same speed on the Snapdragon 8 Elite Gen 5 NPU.

New: Qwen3.5-4B NPU-native Q4_0

File Bytes KL to bf16, task text ↓ KL to bf16, general text ↓ Snapdragon 8 Elite Gen 5 NPU, prompt / generation
unsloth Q4_0 2,583,221,408 0.0464 0.0287 955 / 17.2 tok/s
AutoRound Q4_0 2,611,782,976 0.0363 0.0213
fraQtl Q4_0 2,583,180,384 0.0289 0.0206 950 / 17.1 tok/s

Every operation runs on the Hexagon NPU (0 of 32,165 rejected). Answers on 500 questions: GSM8K 233 vs 233, IFEval 194 vs 190 (difference not statistically significant).

Earlier releases

Model Closer to the original (KL to bf16 or Q8_0), same size Repo
Qwen3-4B-Instruct-2507 −55.9% code/math, −46.4% general vs the community Q4_K_M; 9/9 needles at 262K Qwen3-4B-Instruct-2507-Hi-Fi-GGUF
LFM2-1.2B −43.4% instruction/tool text, −22.7% knowledge/reasoning vs Liquid AI's own Q4_K_M LFM2-1.2B-Hi-Fi-GGUF
Gemma-4-E2B-it −36.0% code/math, −27.2% general vs bartowski Q4_K_M; phone build 21.6 tok/s on an iPhone-16-class device Gemma-4-E2B-it-Hi-Fi-GGUF
Gemma-4-E4B-it −16.2% code/math, −4.2% general vs bartowski Q4_K_M Gemma-4-E4B-it-Hi-Fi-GGUF

Five of our builds are mirrored on the Qualcomm AI Hub community org and are its five most-downloaded models.


▚ On servers: compressed KV cache inside vLLM

Qwen3.8-27B on one H100 at 128K: fraQtl holds 17 users where FP8 KV fits 9; 12.4 tok/s per user vs 9.5 for vLLM native int4 and 19.0 for FP8 at 9 users.

Qwen3.8-27B, 128K context per user, one H100: 17 users where FP8 KV fits 9. Stock vLLM plus one pip install.

KV format Users at 128K Per-user decode
FP8 9 19.0 tok/s
vLLM native int4 17 9.5 tok/s
fraQtl 17 12.4 tok/s

1.31× faster per user than vLLM's native 4-bit KV, using 3% more memory per token. Accuracy: no significant difference (mean KL, 30 documents); equivalence not shown. Against FP8 KV, accuracy is slightly below (mean KL 0.075 vs 0.066, 30 documents), and at 17 users each user decodes slower than FP8 does at 9.

Earlier: 9 users at 128K on one A100 where FP8's best is 4 (Qwen3-4B-Instruct-2507, 134.1 tok/s aggregate, 9/9 retrieval). KV sidecars · runtime


▚ Toolkit

fraQtl toolkit: Hi-Fi GGUF model weights, KV sidecars, Membrane runtimes and the free fraqtl-diagnostic tool, across Qwen, Gemma 4, Llama, Mistral and LFM2.

What Repos
01 · Weights Hi-Fi GGUF models Qwen3.5-4B NPU · Qwen3-4B-2507 · Qwen3.8-27B · Qwen3.6-35B-A3B · Gemma-4-E2B · Gemma-4-E4B · Gemma-4-26B-A4B · Llama-3.2-1B · Llama-3.1-8B · LFM2-1.2B
02 · KV cache KV sidecars Qwen3-4B-2507 · Mistral-7B v0.3 · Mistral-Nemo 12B
03 · Runtime Membrane runtimes fraqtl-sm80-runtime · membrane-llamacpp-runtime · Qwen3.6-35B-A3B MTP runtime
04 · Free tool fraqtl-diagnostic pip install fraqtl-diagnostic · Run in your browser · PyPI · GitHub

▚ Work with us

Bring a model and a task: we deliver a file that fits your device and stays close to the original, with receipts. fraqtl.ai · contact@fraqtl.ai

Paper: arXiv:2604.11501 · Patent pending.