brokkr-smithy-dev's first battery on the new seat scored 12% on contradiction
detection with CoT off, against gen's 81%, while state tracking, deterministic
constraint following, long-context state and the confabulation control all sat
at 100%. That is not general degradation — it is the shape 4-bit input
activations produce on the most reasoning-dense task, which is exactly the
confound flagged when the W4A4 quant was chosen. They have recorded the finding
as CONFOUNDED rather than reporting it as a property of Gemma, and asked for an
A16 build to separate the two.
No quant run was needed: a genuine A16 build of the same checkpoint already
exists on the Hub and is now at /tank/aimodels/gemma4-26b-a4b-it-nvfp4a16
(prithivMLmods, compressed-tensors, nvfp4-pack-quantized, input_activations
null, 17 GB). Same weights, same loader as the live seat, one axis moved.
⚠ Two other repos would have answered the question wrongly and the note in the
env template says so: bg-digitalservices and ManniX-ITA both publish
"Gemma-4-26B-A4B-it-NVFP4A16" whose config declares input_activations num_bits
4 — W4A4 under an A16 name, via modelopt, both 16.46 GB against the real one's
17.93. Using either and seeing T2 stay at 12% would have wrongly convicted the
model.
Running it is a one-line GEMMA4_MODEL swap plus a recreate, because there is no
room for a concurrent seat: GPU0 has 3.5 GiB free with gen and the A4 seat on
it, and GPU1's 19.4 GiB against ~18 GiB of weights is the same sub-GiB headroom
that crash-looped the predecessor this morning. Port and both aliases are
unchanged either way, so no consumer config moves.
vh
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