local-horse/NOTES.md

local-horse — findings log

Running, numbered (N-1, N-2, …). Each entry = something we learned and want to keep: a signature, a gotcha, a decision, a constraint — the stuff we'd otherwise re-derive. NOT the session blow-by-blow (that lives in the weave thread); this is the distilled, durable record a fresh hand reads to catch up fast.

Newest at the bottom. When a truth changes, update every place it lives — a stale note is worse than none.

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N-1 (2026-07-17) — Origin: the K3 repricing that started this

Kimi K3 dropped 2026-07-16 (Moonshot AI, 2.8T-param open MoE, weights due 2026-07-27; API $0.30/M cached-in · $3/M in · $15/M out). Repricing the adventure game's real build tokens (10 sessions, 2026-07-05..17, summed from ~/.claude/projects/-home-obx/*.jsonl, deduped by message id):

• 1,147M cache-read + 18M uncached-in + 3.5M out → ≈ $451 at K3 rates (±30%, session-level granularity) vs ≈ $1,307 at Claude list prices. Actual marginal cost: $0 (subscription).
• The load-bearing fact: agentic coding is ~99% context re-reads, ~1% output. Cached-input price (cloud) / prefill speed + KV-cache persistence (local) dominate everything.
• K3 itself is never local: ~1.4TB weights at 4-bit. "Local like that" = best open model that fits a box.

N-2 (2026-07-17) — The open-model landscape, mid-2026

• GLM 5.2 (Zhipu, MIT, released 2026-06-13): first open model to beat GPT-5.5 on SWE-Bench Pro (62.1; Terminal-Bench 2.1: 81.0). Current open coding champ. Exact memory footprint unverified — check before sizing hardware.
• Qwen3-Coder 480B-A35B: best downloadable coder with known footprint (~270GB @ 4-bit; 35B active). The 80B-A3B variant ≈ 96% of the quality at single-workstation size.
• Kimi K2.6: strongest for agentic stability (consistent tool calling, recoverable failures). ~1T params — barely/slowly fits the workhorse at aggressive quant.
• The lag law (jhestyr's intuition, confirmed): open/distilled models run ≈ 12 months behind frontier, and the lag is stable. A $20k box today ≈ mid-2025 frontier (Sonnet-4-era agentic coding). K3 weights (07-27) will spawn distills sized for the workhorse envelope.
• Capability ceiling, honestly: scoped features / refactors / tests / review on a known repo = credible. Long-horizon overnight autonomy, judgment, Opus/Fable-tier storekeeping = not at any local price.

N-3 (2026-07-17) — GOTCHA: the 2026 DRAM crisis broke the classic build

Server DDR5 RDIMM prices up >400% since mid-2025 (64GB: ~$255 Q3'25 → >$900 Q1'26 → $1,200–2,300 mid-2026; SK Hynix sold out through 2026, fabs pivoted to HBM). Consequences:

• The classic "EPYC + 768GB DDR5 + one big GPU" build went from ~$16k to $28–42k. Dead at $20k.
• Workaround: drop to used Milan + refurb DDR4-3200 (~half the bandwidth, ~1/6 the price) — see BUILDS.md.
• Used 3090s got relatively cheaper (GDDR6X didn't spike) — the multi-card rig gained ground.
• RTX Pro 6000 Blackwell 96GB: Nvidia list jumped 55% in 16 months to $13,250; street/Max-Q hunts lower.
• Relief not expected before 2027. Waiting is a legitimate strategy; re-price at buy time.

N-4 (2026-07-17) — Decision lean (not a decision)

Ezra's recommendation if/when the itch turns real: the workhorse (Milan + 512GB DDR4 refurb + one RTX Pro 6000 Max-Q, ~$15–19k) over the 8×3090 rig — a smarter model that's slower wastes fewer turns than a fast one that circles. Quiet, <1kW, 120V, racks by the Mill, and the skeleton upgrades (RAM, second card slot) without replacing bones. Integration shape: headless Debian, llama.cpp/vLLM serving an OpenAI-compatible endpoint on the tailnet; per mill-is-home-for-workloads it's a Mill annex, not a new species. Sensible trigger to revisit: after 2026-07-27 (K3 weights + first distills) or when DDR5 unclenches.