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Research: quantize bigger bases to fit the Supermicro — is large-model-low-bit a real gain over the current slots? #2245

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@Xore

Upstream reference: https://github.com/aliaihub/awesome-hermes-usecases/blob/main/usecases/dev-local-model-quantization.md

Background

Every LLM slot decision in this stack (#144 -> #158 -> #568) chose among models as shipped — an Ollama library tag or a pre-built HF GGUF at whatever quant its uploader picked. The open rounds (#1795, #1947, #1804) widen the menu but stay on the same axis: existing artifacts, existing quant levels.

This issue is the other axis, the one the referenced write-up is about: start from bases too large to serve at usable precision, generate our own quantized variants, and test whether any of them lands inside the 20 GB envelope faster and/or more accurate than the smaller models we run today. The hypothesis in one line: a base one-to-two size classes above qwen3:14b (27 B–35 B, incl. the A3B MoE class), pushed down a quantization ladder we control, may trade bits we don't need for parameters we're currently leaving on the table.

Why it's genuinely still open here:

Harness we already have (this is applied, not built)

analysis/ghidra/benchmarks/model-quant-benchmark/ — born for the #847 REx86 sweep — implements the complete loop, per model:

  1. download HF snapshot → convert_hf_to_gguf.py → f16 master (snapshot deleted afterward);
  2. llama-quantize down each requested level, skipping anything that already exists (resumable per model and per level);
  3. serve each level via llama-server, score with engine-benchmark/corpus_eval.py on the standard corpus slice;
  4. format results to Markdown with gen_answers_md.py.

Supporting pieces: probe-gpu-capabilities.py for a before/after capability baseline (#637 playbook), and #1947's measurement discipline (error bars, transcripts kept, ≥3 seeded repeats) so the output is comparable with the matrix rebuild rather than another incomparable table.

Two caveats carried forward:

Target hardware

Supermicro homeserver (xore@192.168.42.250), Ada 20 GB as serving card (#602, #1539), production contexts as loaded today (8k; 32k where the slot uses it — see #568's context-ceiling question).

Run shape

  1. Base selection — at least two bases ≥ 24 B instruct (one dense, one MoE/A3B arm for latency), prioritising models whose published quants either overflow 20 GB at usable widths or stop at unusably low bits — those are exactly the levels worth generating ourselves. Existing shipped-quant candidates stay in Benchmark round: new derestricted HF candidates (XORTRON, GLM-4.6-Derestricted, gemma-4 heretic) within the 20GB VRAM budget #1795/One benchmark, every model, every aspect: rebuild the model matrix on current hardware with error bars #1947; those rows feed step 4's comparison, not duplicated here.
  2. Ladder generation — f16 master → quant levels from the largest that fits 20 GB including KV-cache headroom at production context, downward through Q2-class. Record per-level file size, nvidia-smi residency, and offload split.
  3. Evaluation — every level that loads, regardless of expectation: prefill/decode tok/s, VRAM+KV headroom at 8k and 32k, corpus_eval score × ≥3 seeded repeats, transcripts kept. Levels that spill to RAM are measured and reported, not skipped; timeouts are recorded results (One benchmark, every model, every aspect: rebuild the model matrix on current hardware with error bars #1947 rule).
  4. Comparison plane — winners must beat (a) today's production slots as deployed and (b) the best shipped-quant rows for the same size class from Benchmark round: new derestricted HF candidates (XORTRON, GLM-4.6-Derestricted, gemma-4 heretic) within the 20GB VRAM budget #1795/One benchmark, every model, every aspect: rebuild the model matrix on current hardware with error bars #1947, on the agreed metric: quality within noise at equal-or-better decode tok/s, or better quality at equal throughput.
  5. Verdict as a record — a winner promotes only via a fresh approval record with re-run gates per Re-evaluate LLM model selection (ghidra/revdeck/sessions) now that GPU VRAM is confirmed ~20GB, not 8GB #568's audit-trail rule (never patching approved-models.json in place) + follow-up issue for deployment. A null result closes this issue with the negative answer and its numbers — equally valuable: it proves the size ladder adds nothing over shipped quants and stops the hypothesis being re-raised.

Out of scope

Related: #568, #602, #598, #637, #847, #356, #1539, #1795, #1947, #1804

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