DeepSeek v3.2-Exp, Claude Sonnet 4.5, and more
Lot of interesting stuff, I don’t know where to start!
I’ll start from DeepSeek, since I am a stan.
DeepSeek-V3.2-Exp. It’s a new model built on V3.1-Terminus, and it introduces DeepSeek Sparse Attention, which is a new architecture module that enables fine-grained sparse attention, selecting top-k key-value entries for each query using efficient FP8 operations and lightning indexer. It was built by training five RL-specialized models (math, competitive programming, agentic coding, logical reasoning, and agentic search) using GRPO, then distilling them into the final 685B-parameter model. It comes with a 6-page paper which does not seem to be really specific, but it really seems that they are silently cooking and figured something out. Anyway, 10x cheaper inference at 128k tokens, with API prices cut by 50%+. They insist on it being experimental. Matches V3.1-Terminus on most benchmarks, but shows slight degradation in reasoning-heavy tasks like GPQA due to generating fewer reasoning tokens. It seems they cracked cheap, long context for LLMs. I’ll try to write more on the paper when I have time.
Claude 4.5 Sonnet – boring stuff? Anthropic made a bold statement about their latest model: the world’s best coding model. I’m not a fan of benchmarks, it just seems to be superior of Opus 4.1, Sonnet 4, GPT-5-Codex, GPT-5 and Gemini 2.5 Pro on a lot of benchmarks. My personal highlights: extended thinking mode, which allows sustained focus on multi-step tasks for over 30 hours; it’s trained on a proprietary dataset mix including public internet data (up to July 2025). Post-training uses RL from human and AI feedback.
Bonus: LoRA without regret. New blog post from Thinking Machines that experimentally shows that LoRA fine-tuning matches full fine-tuning’s sample and compute efficiency for post-training on smaller datasets when using high ranks and applying it to all layers (especially MLPs). Worth reading.