project: localvm-research document: README author: Simon-Pierre Boucher contact: contact@spboucher.ai created: 2026-08-11 modified: 2026-08-12 status: reviewed
localvm-research
Running LLMs larger than memory on a consumer Mac
Live research platform: www.localvm.dev — every hypothesis, result, figure, and failure, browsable.
Author: Simon-Pierre Boucher · contact@spboucher.ai
The question
Can an existing pretrained LLM whose memory requirements exceed a consumer Apple Silicon Mac be transformed post-training into an execution representation whose instantaneous working set is dramatically smaller than the full checkpoint — while preserving most of its capabilities?
The project's central distinction, which everything here tries to decouple:
total model size ≠ resident model size ≠ bytes read per token ≠ parameters required for THIS tokenThis is a falsification-driven research project run under a strict charter (CLAUDE.md): hypotheses are registered with explicit kill criteria before experiments run, no result is reported from an uncommitted tree, every result file embeds a hardware manifest, and negative results are kept and published. The full audit trail lives in the append-only research log.
Headline results
All measured on the primary research machine — Apple M5 Max, 6P+12E CPU, 40-core GPU, 48 GB unified memory, 2 TB AP2048Z NVMe, macOS 27.0.
| # | Result | Key numbers |
|---|---|---|
| 1 | SSD substrate envelope (expH) | device ceiling ≈ 13.1 GB/s (iostat-validated); 4 KiB QD1 random = 67 MB/s → 1 MiB QD8 = 13.8 GB/s (200× spread); saturated Metal GPU costs < 5% of SSD throughput |
| 2 | Margins predict disagreement (expG) | AUROC 0.85–0.98 (3/4/8-bit); domain-uniform; escalation for 99% agreement falls with scale: 36.6% → 22.6% (1.7B → 8B, 4-bit) |
| 3 | Naive 2-bit is dead (expG) | affine 2-bit: 3% greedy agreement, KL ≈ 11.9 — the 2–3-bit cliff, measured |
| 4 | Progressive residual coding works (expD) | hidden-state error ÷5 per stage; two-tier margin policy: 97.6% agreement @ 35% escalation |
| 5 | Three escalation routes refuted (expF/A/B) | layer sensitivity spread only 1.5×; 95% FFN energy needs 77% of 64-neuron blocks; 128-token working-set union = 99.9% — dynamic sparsity paging does not transfer to dense SwiGLU models |
| 6 | Quality–bytes continuum (candidate, 1.7B) | verify-all output statistically = resident-q8 (bf16 judge −0.1297 vs −0.1328) at 237 MB/token streamed — 9× under the checkpoint; τ knob: 150/211/237 MB/token ↔ 47%/83%/~100% of the q4→q8 gap |
| 7 | Out-of-core at 32B (candidate, scale) | q8-32B (34.8 GB) cannot co-reside with the q4 base on 48 GB — streamed layer-by-layer at ~11.6 GB/s; +0.28 nats over pure-q4 (the only fitting config) at 3.7 GB/token (9.4× under checkpoint), 1.69 tok/s |
| 8 | Two macOS measurement traps | F_NOCACHE does not evict resident pages (naïve "cold" benchmarks read RAM at 42–115 GB/s); Metal prefill vs incremental decode flips 1.56%/token of a model's own greedy argmax — token-exact reproduction is not a coherent target |
The architecture — margin-gated deferred refinement
Selected by the evidence (not by preference — see the candidate ranking and three refutations above):
- Resident base — the q4 quantization of the model lives in unified memory and generates greedily, recording each decision's top-1 logit margin (a free byproduct of the forward pass).
- Deferral — decisions with margin < τ are flagged; generation never blocks.
- Amortized verification sweeps — every W tokens, the same checkpoint's q8 variant teacher-forces the window in one pass through a persistent incremental verify-KV-cache. When q8 cannot co-reside (the target regime), it is streamed layer-by-layer from SSD (materialize → compute → re-lazify) — one sequential pass over the checkpoint per sweep, exactly the access pattern the measured SSD envelope rewards.
- Rollback — on the first checked flip the runtime trims both KV caches, accepts the q8 token, and resumes.
τ is a runtime knob that prices output quality in verification bytes — a property no static quantization format offers.
Implementation: experiments/candidate_01/implementation/
(runtime.py — generation/deferral/rollback loop; streaming_verifier.py —
per-layer weight streaming on unified memory).
The experimental campaign
Every experiment has a preregistered hypothesis.md (seven-field scientific
block with falsification criterion) and a post-run analysis.md.
| Experiment | Question | Verdict |
|---|---|---|
| expH — SSD feasibility | Can the internal NVMe sustain weight-streaming rates? | ✅ Confirmed — with a strict ≥256 KiB / QD≥4 / sequential contract |
| expG — decision stability | Does the cheap pass's margin predict disagreement? | ✅ Confirmed (AUROC 0.85–0.98, improves with scale) |
| expD — progressive reconstruction | Do residual ladders converge? Does gating compose? | ✅ Confirmed (with an honest static-parity caveat) |
| expF — error accumulation | Is quantization damage concentrated in layers? | ❌ Refuted — diffuse (1.5× spread), repair is cooperative |
| expA — weight concentration | Is per-token FFN importance pageable at block granularity? | ❌ Refuted — neuron-level concentration exists but is scattered |
| expB — token stability | Is the important-block set temporally cacheable? | ❌ Refuted — union ≈ 100% within 128 tokens; Jaccard ≈ random null |
| candidate_01 — 1.7B | Does the assembled runtime deliver a quality–bytes continuum? | ✅ q8-equivalent quality at 9× fewer bytes |
| candidate_01 — 32B scale | Does it work when the verifier physically cannot fit? | ✅ +0.28 nats over the only fitting alternative |
The refutations are load-bearing: they killed the fashionable design (dynamic sparsity paging à la DejaVu / LLM-in-a-flash) on modern dense architectures with numbers, and left batch-amortized verification as the only surviving route — which the prototype then validated.
Novelty, honestly stated
An adversarial prior-art search (novelty_check.md, 45 sources) found every component anticipated — precision-tiered draft/verify (QSpec, Apple QuantSpec), resident-draft + flash-streamed target (Lever 2026, CATS 2026), uncertainty-gated verification (U-HLM/UGSD, vs cloud), window-amortized verification (SpecExec), MLX layer streaming (mlx-flash). Four narrow claims survived: (N1) margin-gating of the same model's higher-precision weight-streaming I/O on one machine; (N2) bytes-streamed-per-token vs checkpoint size as the explicit objective, with τ as the knob; (N3) the training-free same-checkpoint q4/q8 split demonstrated where the verifier cannot reside; (N4) the unified-memory/Metal instantiation. Attribution obligations are recorded and the check should be re-run before any external submission.
Repository structure
localvm-research/
├── CLAUDE.md # research charter (methodology contract)
├── research/ # the scientific paper trail
│ ├── LOG.md # append-only research log (every decision)
│ ├── state_of_the_art.md # Phase 2 — technique taxonomy, overlap analysis
│ ├── research_gaps.md # Phase 3 — 24 falsifiable gaps (G01–G24)
│ ├── candidate_ranking.md # Phase 4 — 10-axis scoring, 4 candidates
│ ├── novelty_check.md # Phase 11 — adversarial prior-art verdict
│ ├── bibliography.md # 304 sources with URLs and access dates
│ └── notes/ # 5 Phase-1 literature theme notes
├── experiments/
│ ├── micro/expA…expH/ # preregistered micro-experiments
│ └── candidate_01/ # the prototype runtime + 1.7B/32B benchmarks
├── benchmarks/
│ ├── hardware_manifest.py # macOS-native fingerprint (embedded in results)
│ └── datasets/eval_prompts.json # 6-domain eval prompts (code/math/chat/FR/EN/reasoning)
├── results/ # raw JSON results (commit + config + seed + manifest)
├── src/localvm/ # library (quality/decision_stats.py, backends, …)
├── tools/ # check_headers.py, new_experiment.py, make_pub_figures.py
├── docs/publications/ # official technical reports (TR-01) + SVG figures
└── web/ # the public research platform (Express, deployed)Reproduce it
# 1. Environment (Apple Silicon Mac, macOS 14+)
python3 -m venv .venv
.venv/bin/pip install mlx mlx-lm numpy
# 2. Fingerprint your machine (embedded in every result)
python3 benchmarks/hardware_manifest.py
# 3. Substrate envelope (~15 min, writes results/expH_ssd_feasibility/)
cd experiments/micro/expH_ssd_feasibility && ../../../.venv/bin/python benchmark.py
# 4. Decision stability (~10 min, downloads Qwen3-1.7B-bf16)
cd ../expG_decision_stability && ../../../.venv/bin/python benchmark.py
# 5. The prototype (build quantized artifacts once, then run)
cd ../../candidate_01
../../.venv/bin/python benchmark.py --build
../../.venv/bin/python benchmark.py # 1.7B continuum
../../.venv/bin/python benchmark_scale.py # 32B out-of-core (downloads ~52 GB)
# 6. Regenerate all publication figures from committed results
python3 tools/make_pub_figures.py
# Quality gates
python3 tools/check_headers.py # mandatory header check (CI-style)Every benchmark writes results/<experiment>/<UTC timestamp>/results.json
with the full config and hardware manifest embedded.
Publications
- TR-01 — Margin-Gated Deferred Refinement: Streaming Higher-Precision LLM Quality Than Fits in Memory on Consumer Apple Silicon (August 2026) — the complete write-up with figures, prior-art attribution, and limitations. Also on the platform: localvm.dev/publications.
Known limitations & roadmap
Recorded in TR-01 §7 and the research log — the honest list: prototype speed (1.69 tok/s at 32B) is below interactive; no resident-q5/q6 baseline at 32B yet (they fit in 48 GB and may dominate at that scale — the architecture's necessary regime is 70B-class, untested); the 8B judge is a proxy with no error bars at n=12; no task-level benchmarks yet; one model family, one machine. Next: resident q5/q6 baselines → task benchmarks (GSM8K-class) → τ calibration on real quantized-artifact margins → 70B point → TR-02.
Author & citation
Simon-Pierre Boucher — contact@spboucher.ai
@techreport{boucher2026localvm,
author = {Boucher, Simon-Pierre},
title = {Margin-Gated Deferred Refinement: Streaming Higher-Precision
LLM Quality Than Fits in Memory on Consumer Apple Silicon},
institution = {localvm-research},
number = {TR-01},
year = {2026},
month = {August},
url = {https://www.localvm.dev/publications}
}Citation metadata: CITATION.cff.
License
All rights reserved (research code) — © 2026 Simon-Pierre Boucher. See LICENSE. The research trail is public for reading and verification at www.localvm.dev; reuse requires written authorization.