If you are wondering why Ornith 1.5 35B A3B with MTP is so slow, this is why

Reddit r/LocalLLaMA Models

Summary

The Ornith 1.5 35B A3B model's MTP tensors appear to be uninitialized, causing poor speculative decoding performance, and grafting the trained head from Qwen3.6-35B-A3B improves speed by 29%.

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Cached at: 08/20/26, 08:56 PM

ornith-ai/Ornith-1.5-35B-A3B · mtp.* tensors look like random init, not trained weights

Source: https://huggingface.co/ornith-ai/Ornith-1.5-35B-A3B/discussions/10 First off, 1.5 is seriously impressive work. The 35B-A3B numbers on Terminal-Bench and SWE-bench for 3B active params are remarkable, and it’s been great to run locally. Thank you for releasing it under MIT.

While poking at the weights with some remote tensor probes I think I found a small packaging issue: the mtp.* tensors don’t look trained. Every projection (q/k/v/o, fc, the experts, shared_expert) has std of exactly 0.0200 with clean Gaussian stats, which is just initializer_range=0.02. The norm weights sit around 0.02 where you’d expect ~1. For comparison, Qwen3.6-35B-A3B’s MTP head (same shapes) has fc kurtosis in the hundreds and norms between 0.87 and 1.93.

It shows up in practice too. Used as a speculative draft in llama.cpp (b10507, Q4_K_M main + Q8_0 draft on a 3090) the shipped head accepts about 13% of drafted tokens, mean run 1.5, which is basically chance.

The nice part: since the 1.5 tower is only ~0.2-1% away from Qwen3.6 in cosine, grafting Qwen3.6’s trained head across just works. Acceptance goes to 55-75% (mean run 3.2-4.0) and generation goes from 131 to 169 tok/s on my box, same outputs on a small pass@1 set. So everything around the head slot is healthy, and a free +29% is sitting there for anyone who wants it.

Merged model demonstrating it, numbers in the card:https://huggingface.co/EryriLabs/Ornith-1.5-35B-A3B-BigBang-MTP

Happy to share the probe scripts if useful. Was the untrained head reserved for a later drop, or did a trained one just miss the upload? Either way, thanks again for the model.

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