This is true, but I think it understates the problem. I did a task I've done with a bunch of small models lately (https://github.com/swelljoe/flar/pull/17), and it did an excellent job, the best of any self-hostable model. But, it took eleven (11!) hours on my dual GPU setup. It really chewed on it, and spent a lot of time checking and re-checking. It is by far the slowest model I've used for the task. GPT 5.5 did a similar task in about 20 minutes. Most big models took about an hour or so, and most small models needed a couple of hours (but did a worse job).
I have a private benchmark for disassembly of 80s CPU code and Qwen either does really well or spirals into insanity (looping, failing to call tools). Nemotron is beating it pretty handily, despite being considered a weaker model.
I think it was overtrained and I am starting to suspect that 27B is just not enough to be psychologically stable.
The big problem with overthinking on a dense model is obviously the speed hit you take. Going from Qwen 35BA3B to 27B for me is about 7-8x slower (should be ~9x?). This makes me a lot less patient for useless thinking tokens.
I’d want to compare this to the new Muse 30B model which is super terse and has a whole different way of thinking (no “Wait,”) and in my experiments was way more token efficient to the point that the absolute tok / s didn’t really matter.
Both applications work correctly and fulfill the requirements. The Qwen one (which used the default xhigh reasoning setting) is massively over-engineered. The Glimmer one used whatever their default in LM Studio is and I would argue is a tiny bit under-engineered.
Weirdly the Glimmer one doesn't work with images on other domains like https://static.inaturalist.org/photos/714731804/large.jpg - it fails with a CORS error, but you don't need CORS to load images and detect their width and height, and the Qwen one handles that URL just fine.
That's because Glimmer added this unnecessary line:
--thinking-budget and --thinking-message is all you need in llamacpp to keep it progressing.
the message can be some combination of tool calling, summarizing, etc. It's overthinking often is a bunch of recursion, so simply stopping t and redirecting is all you need to do.
If someones building a harness for llamacpp, you can set this per message, so it's possible to dynamically control it by watching for the expansion of the thinking traces, and redirecting it.
I use the message to tell it to use subagents, add additional logging and to use opencode's dynamic context pruning.
Unfortunately in xhigh thinking it goes down rabbit holes in such an extreme depth-first way, that whenever you choose to cut it off, there is a very good chance it will not have got round to musing on even half of the prompt! It doesn’t really obviously loop in xhigh, so I am not sure if an “overthinking guard” proxy would have much to go on, but it does obsessively ruminate on edge cases. I have seen it overcomplicate simple code as a result even in my limited testing.
Probably the better solution if you want it to be quicker but still fairly thorough appears to be to configure reasoning effort instead of thinking budget. It seems to do very well still even on the Low setting; on the Medium setting it can get stuck in loops like 3.6 does.
I think xhigh reasoning effort was an absurd choice for a default, and so was not sorting out the chat template so LM Studio could offer the reasoning effort dropdown.
to the point though: most of that overthinking is useless if you have a proper redirect message. So setting arbitrary budget and getting it a good message will do the trick regardless of what type of thinking it's doing. The reason thinking seems to work is that it's just trying to find an optimum outside the local optimum, and the thinking trace helps find it.
The only think I could think that'd be better than the --reasoning-budget would bet a budget jitter just in case it really is repeating a pattern and you want to escape it arbitrarily, otherwise yes, it could keep looping if you're always cutting at the wrong time.
I had to fix this on 35B A3B -- I have a proxy that just shuts it down if it gets to 2K thinking tokens and injects something like "We have thought enough, let's begin working." and it almost always finishes the turn then. It rarely needs more than 2K thinking tokens and if it does there is always next turn. I would need to see what 27B is actually doing, but these smaller Qwen models seem prone to this.
I hope Apple does end up moving to HBM. Unified memory has been a huge godsend, but the low memory bandwidth is just such a killer. Even/especially on M5, where the available compute is starting to starve incredibly badly on ML workloads.
I think it was overtrained and I am starting to suspect that 27B is just not enough to be psychologically stable.
I’d want to compare this to the new Muse 30B model which is super terse and has a whole different way of thinking (no “Wait,”) and in my experiments was way more token efficient to the point that the absolute tok / s didn’t really matter.
Qwen: https://gist.github.com/simonw/121ad098860028b2fab603fa12da1... - 17,576 reasoning tokens, produced this HTML result: https://static.simonwillison.net/static/2026/qwen-over-think...
Glimmer: https://gist.github.com/simonw/51e8ddb2ee597a5005fa63bd4927d... 1,021 reasoning tokens, this HTML: https://static.simonwillison.net/static/2026/glimmer-bbox.ht... - ugly but functional.
In both cases paste in the URL https://static.simonwillison.net/static/2026/two-pelicans-on... to see them work.
Both applications work correctly and fulfill the requirements. The Qwen one (which used the default xhigh reasoning setting) is massively over-engineered. The Glimmer one used whatever their default in LM Studio is and I would argue is a tiny bit under-engineered.
Weirdly the Glimmer one doesn't work with images on other domains like https://static.inaturalist.org/photos/714731804/large.jpg - it fails with a CORS error, but you don't need CORS to load images and detect their width and height, and the Qwen one handles that URL just fine.
That's because Glimmer added this unnecessary line:
the message can be some combination of tool calling, summarizing, etc. It's overthinking often is a bunch of recursion, so simply stopping t and redirecting is all you need to do.
If someones building a harness for llamacpp, you can set this per message, so it's possible to dynamically control it by watching for the expansion of the thinking traces, and redirecting it.
I use the message to tell it to use subagents, add additional logging and to use opencode's dynamic context pruning.
As such, we'll just whisper here _skill issue_.
Probably the better solution if you want it to be quicker but still fairly thorough appears to be to configure reasoning effort instead of thinking budget. It seems to do very well still even on the Low setting; on the Medium setting it can get stuck in loops like 3.6 does.
I think xhigh reasoning effort was an absurd choice for a default, and so was not sorting out the chat template so LM Studio could offer the reasoning effort dropdown.
The only think I could think that'd be better than the --reasoning-budget would bet a budget jitter just in case it really is repeating a pattern and you want to escape it arbitrarily, otherwise yes, it could keep looping if you're always cutting at the wrong time.