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by neomindryan 17 days ago
Author here. The short version: a viral post ran Gemma 4 on a 2016 Xeon; my Xeons are 2013, and the fork it used assumes AVX2, which Ivy Bridge doesn't have. The build failure was easy. The fun bug was the silent one: two MoE graph ops with no dispatch case on non-AVX2 builds, so every expert FFN output was uninitialized memory. Deterministic, NaN-free, fluent-looking multilingual gibberish.

The fix is open upstream as PR #2138 (https://github.com/ikawrakow/ik_llama.cpp/pull/2138), awaiting review. Fair warning on the AI angle: the patch was written by Claude at my direction. The post is explicit about which parts were me and which weren't. Happy to answer questions about either the bug or the workflow.

2 comments

Why is the post AI-generated? If you're going to make something for us to read you pay us the courtesy of actually writing it first.

https://www.pangram.com/history/61fbc90e-180d-4d91-a85d-16ff...

This reads as pretty clearly AI-generated text, which is against HN guidelines.
The PR? He said it was AI in the comment you replied to...

I don't think the post itself reads like AI at all, but that's just me.

I think "this" refers to its parent comment. Part of it sounds like Claude wrote it. AI-generated comments aren't allowed on HN.
Indeed, I was referring to the parent comment.
The post is absolutely LLM-generated. “Punchy” short sentences, “… has quietly come to mean …”, “The optimized paths weren’t there to execute.”
The post itself is totally AI-generated. It has tons of tells, in addition to Pangram saying so.

https://www.pangram.com/history/61fbc90e-180d-4d91-a85d-16ff...

Here's the thing: life also imitates art. If you invert your load-bearing assumption, it could be that he just reads too much slop. But my honest take? You might be right.
stopitgetsomehelp.gif ;-)