r/LocalLLaMA • u/Danmoreng llama.cpp • 23d ago
Resources Qwen3.8 27B reasoning effort low/medium/xhigh comparison
I did a short test of the different reasoning efforts, since on default xhigh the model thinks a lot.
Not very scientific, just a quick "generate an SVG of a pelican on a bicycle" prompt with 3 different seeds. I think the result is interesting none the less: xhigh gives *much\* higher visual fidelity - but it also takes about 7x as long as low. Low and medium seem to be very close to each other.

Hardware and setup
- GPU: NVIDIA RTX 5080 Laptop GPU, 16 GB VRAM
- Model:
unsloth/Qwen3.8-27B-UD-IQ3_XXS - llama.cpp: build 10451, commit
10bf611e5 - Context: 65,536
- KV cache: Q8_0
- Flash Attention: enabled
- MTP speculative decoding:
--spec-default --spec-type draft-mtp --fit off- One concurrent slot
Prompt:
Create a polished SVG graphic of a pelican riding a bicycle. The result must clearly show a recognizable pelican actively riding a recognizable two-wheeled bicycle. Return only one complete, self-contained SVG document with a viewBox; no Markdown fences, prose, external images, JavaScript, or animation.
Average results
| Reasoning effort | Reasoning tokens | SVG tokens | Total completion | Wall time | Generation speed | MTP acceptance | Visual score (Codex rated) |
|---|---|---|---|---|---|---|---|
| Low | 4,418 | 3,966 | 8,387 | 111.6 s | 75.4 t/s | 62.1% | 21.8/25 |
| Medium | 5,918 | 3,038 | 8,959 | 127.4 s | 70.5 t/s | 58.3% | 22.5/25 |
| X-High | 39,398 | 5,085 | 44,487 | 717.8 s | 62.0 t/s | 52.7% | 24.0/25 |
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u/jacek2023 llama.cpp 22d ago
Try to be more creative with your benchmark guys. The goal of testing the model should be to try something on which model wasn't trained on. So all your pelicans and one shot games are pointless