By Simon Gonzalez de Cruz (follow the build in public on X @KyaniteLabs_). Arc close, 2026-08-21. The whole story, corrected on the record.
We asked a simple question: can a $1,400 mini-PC serve a 27B model the way big rigs do? This note closes the book. Every claim below has a raw log behind it, in the public repo, with its methodology.
The rig
AMD Strix Halo, 64 GB shared memory, open tooling (llama.cpp), one free Apache-2.0 model. No cloud, no rentals.
The ceiling
Exact needle retrieval at every tested depth, two seeds, up to 261,130 of 262,144 tokens — 99.6% of the window, the literal ceiling. Warm follow-ups on a loaded 198k-token document: exact quote in 23.8s, yes/no in 10.0s, one-line summary in 17.5s. Format does not matter: prose or code, exact either way; described-in-words, every part comes back in order. Raw: nativemax-results.log · quote-rerun-results.log.
The bug we owed you
Mid-arc, long-context and vision silently broke on this GPU class. Our first read blamed the model — wrong. We bisected it to one upstream change (c7d8722), reported it, fixed it locally, and validated the upstream fix on our silicon: 9/9 identical answers, paired. The correction is in the repo, on the record. Degeneration was the instrument, not the model. Raw: issue 26209 · pr25863-validation.
The frozen config
Weights Q4. KV cache light (q4_0) — after measuring the trade: the heavy option buys up to ~3 seconds on follow-up questions (sub-second to 2.8s measured at the half window) for ~4 GB; we kept the room. Speculation: the shipped setup, verified fastest of four by paired walls (15.1s per 200-word answer vs 17.8s with it off). Context: the full 262,144. Thinking: off by default, hard problems think — measured across three difficulty bands. Vision: works, 6/6 on real browser screenshots. Raw: config-27b-2026-08-21.
What this proves
A complete serving story — speed, memory, quality, failure modes, and the fix trail — measured on hardware anyone can buy, with every number reproducible from the repo. That is the standard we wanted to set.
The rig stays on this frozen config. Next chapter when we open it.
Conditions: $1,400 GMKtec EVO-X2, Qwen3.8-27B Q4_K_XL, llama.cpp ROCm, 262,144-token window, K+V q4_0, temperature 0. Arc close. A table with linked logs: github.com/KyaniteLabs/qwen38-27b-strix-halo.