This repository provides GGUF quantizations for Qwen3.8-27B optimized using ZB-ZipBrain, a custom mixed-precision quantization methodology that optimizes LLM tensor bit allocation using rate-distortion marginal cost combined with importance matrix calibration. It automatically identifies Pareto-optimal BPW "sweet spots" to maximize model quality while fitting precise VRAM and memory footprints.
Specifically optimized to fit mainstream GPUs within a 16GB VRAM budget at around 4 BPW, and even 12GB VRAM cards at around 3 BPW.
For filenames marked with v5, I combined ZB + Pelicanmaxxing for visual evaluation, iteratively tuning until the output reached the most stable quality before locking it in.
The newly released Unsloth Dynamic v3 is truly the best value for performance right now.
My ZB is just an experiment, feel free to check it out for fun :)
Update: Aug 22, 2026
Quant release ZB-4.00 BPW runs cleanly on 16GB VRAM with MTP support and up to 95K context length.
Update: Aug 24, 2026
ZBv3-4.00BPW update maintaining size with KLD and Same top-p performs slightly better. ZBv2-4.00BPW -> ZBv3-4.00BPW: output weights were bumped from Q5_K to Q6_K. Testing shows sharper, more consistent outputs and better one-shot performance. => Go with ZBv3-4.00BPW.
ZB3.7-MIN ⚔️ empero-ai/Qwen3.8-27B-Ridge. 🤣
I have just updated empero-ai/Qwen3.8-27B-Ridge. benchmarks; comparing my ZB 3.7bpw metrics, it looks like it easily beats down Qwen3.8-27B-Ridge
Update: Aug 26, 2026
ZB3.7-MIN-v4 update PPL slightly better
Update: Aug 28, 2026
All use Q6_K for output.weight
Please prioritize later development versions, I have removed older ones because I was not satisfied with them.
Quant release 4.00bpw & 3.88bpw v5 (v5 = ZB + Pelicanmaxxing and visually check for other aspects of stability. )
ZB3.88-MIN-v5-IQ3_M_XL ⚔️ UD3-Q3_K_XL 😎 If anyone has used this pair, please let me know what you think.
3.0BPW-IQ3_XXS: New release size only 9.62 GB 🙀 with metric comparable to Ridge—3.7 bpw.
Update: Sep 5, 2026
ZB4.00-MIN-v5.1-IQ4_XS This version has been updated so that all tensors are ≥ IQ3_XXS , previous version contained some IQ2_S tensors. Quality is slightly improved, new file size saves 50MB.
Update: Sep 8, 2026
ZB3.73-MIN-v5.1-IQ3_M_L Added new 3.73 bpw. Updated all tensors ≥ IQ3_XXS, quality is slightly improved. Change for ZB3.70-MIN-v4-IQ3_M_L.
Added HumanEval, MBPP benchmark
Recommended Settings: Set reasoning_effort to medium.
At this BPW level, it delivers much more stable outputs and fits well in agentic workflows.
You can also use the default settings for higher quality, though it will take longer.
