The GX10 runs run 3c at about 79.3 s/it with 35 GB of headroom, which puts
604 steps at 13.3 hours against ana-ml2's 2.2 to 2.7. Six times slower
where raw compute predicts 2.7, which points at memory bandwidth rather
than FLOPs -- recorded as a hypothesis, since confirming it needs a
bandwidth-bound microbenchmark nobody has run.
That reverses the standing plan. Moving run 3c here was framed as the
power answer, but the run did not die because ana-ml2 is unreliable. It
died because save_steps was 100 and the breaker tripped at step 80, so no
checkpoint existed. save_steps is now 50, which caps a power event at
about eleven minutes. Trading 2.5 hours for 13.3 buys insurance against a
risk already engineered out.
Also records the five launch failures and their causes, and the one that
matters most: the attention-backend trap was present and I first declared
it absent. I checked whether flash-attn was installed, which is the wrong
discriminator; the harness sets flex_attention explicitly in code. Absence
of an alternative is not evidence of the default. The probe now reads the
resolved backend back off the loaded model, and flex_attention does
compile and run on sm_121.
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