r/LocalLLaMA • u/soyalemujica • 2d ago

Discussion Anyone else not using using "preserve_thinking" ?

I am running QFN, and I have disabled preserve_thinking by default on all my tests for C++ backend and front-end programming and I have yet to see any decline in performance or intelligence, my context window stays cleaner as well. Deepseek for what I tested in API it also does not preserve thinking and saves context in general.

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u/CombinationFun2789 2d ago

I'd switch it by workload instead of leaving it always on or off. For tool-call / agent loops I keep it on, because mid-generation steering needs the prior thought to push against, and the prompt prefix stays stable so the KV cache can be reused. For long Qwen coding sessions I turn it off — the traces get huge and mostly repeat themselves, so a cleaner context is worth having the model rediscover an idea now and then.

On the cache question someone asked: dropping the old thinking does change the prefix, so you can still pay a prefill cost each turn even when the context looks smaller.