Qwen3.6-27B — PrismaAURA 5.5 (Blackwell, NVFP4 + FP8 + BF16)

PrismaQuant export of Qwen/Qwen3.6-27B for vLLM compressed-tensors serving on NVIDIA Blackwell. This is the PrismaAURA artifact: a per-Linear mixed-precision allocation chosen by AURA — PrismaQuant's production-faithful KL–Fisher allocator — over the full NVFP4 / FP8 / BF16 format menu.

Where the earlier PrismaSCOUT artifact used only NVFP4 + BF16, PrismaAURA adds the FP8 middle rung to the menu, so the allocator can spend an extra ~4 bits on the Linears that need it instead of jumping all the way to 16. ~5.5 bits per quantizable parameter; 23 GB on disk.

Tool-use fidelity (ToolEvalBench, hardmode, deterministic)

Tool-use is the metric we weight most: a small probability shift at a decision point can flip a tool call. On ToolEvalBench (--no-think --hardmode, sequential, temperature=0, seed=1234), PrismaAURA scores the highest of the entire family — above full precision:

Same harness, same seed for all three. PrismaAURA preserves tool-calling behavior at least as well as the unquantized model on this benchmark, at 5.5 bpp.

Served KL-vs-BF16

KL divergence measures how far the quantized model's full output distribution has drifted from the original full-precision model (0 = identical). Measured on a held WikiText split (exact vLLM, n=8 × seqlen 512, vs the BF16 teacher in the same session):

• Served KL-vs-BF16: 0.0342

Against the prior AURA research build at the same bpp (NVFP4+BF16 only, earlier render/export code), this is a −40.9% reduction in served KL — driven by the full FP8 menu, a corrected per-Linear render (fixed GPTQ damping, scale-faithful NVFP4 export), and a corrected calibration probe. (Single-draw served KL; the direction is corroborated by the deterministic ToolEvalBench result above.)

What AURA does

A modern LLM has thousands of weight matrices, each storable at one of several hardware precision formats. AURA splits quantization into two questions and answers the hard one by measurement:

• Local (well studied): given a fixed format, round this one matrix well — GPTQ, implicit clipping, activation-order. PrismaAURA runs the full deliberate render under every Linear.
• Global (PrismaQuant's contribution): how many bits should each Linear get, and in which format? AURA prices each (Linear, format) by a KL–Fisher quadratic — the second-order effect of that Linear's quantization error on the model's output distribution, measured with stochastic probes through the real model — and solves a multiple-choice knapsack over the bit budget. A heterogeneous per-Linear assignment extracts quality no single-format method structurally can.

Artifact details

• Source model: Qwen/Qwen3.6-27B
• Export format: vLLM compressed-tensors, mixed precision
• Format menu: NVFP4 (group 16) + FP8 (E4M3 dynamic) + BF16, allocated per-Linear by AURA
• Target hardware: NVIDIA Blackwell (NVFP4-native)
• MTP tensors: included (BF16 passthrough)
• Size on disk: ~23 GB (~5.5 bpp over quantizable parameters)
• Passthrough dtype policy: source dtype preserved (no silent FP32 upcasting)

This is a quality-first operating point: it is larger than the 20.17 GB PrismaSCOUT artifact, not smaller. A matched-footprint AURA point is in progress. Downstream task evals (GSM8K / IFEval / MMLU) are forthcoming; the numbers above are what has been directly measured.

Serving

vllm serve rdtand/Qwen3.6-27B-PrismaAURA-5.5bit-vllm \
  --quantization compressed-tensors \
  --trust-remote-code \
  --max-model-len 32768 \
  --kv-cache-dtype fp8 \
  --enable-prefix-caching \
  --reasoning-parser qwen3 \
  --enable-auto-tool-choice \
  --tool-call-parser qwen3_coder \
  --speculative-config '{"method":"mtp","num_speculative_tokens":3}'

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PrismaQuant — mixed-precision LLM quantization that chooses the right format per Linear on real end-to-end KL. Contact: robert.tand@icloud.com