LiveBench 2026 Long-Horizon Leaderboard
LiveBench 2026 Long-Horizon measures multi-step tasks that a model has to carry through many steps to finish. It belongs to the 2026 LiveBench release (first snapshot September 2, 2026), a redesigned LiveBench in which each of seven categories is scored by a single task and questions are refreshed to limit training-set contamination. It is a different test from the original LiveBench boards, so the scores are not comparable.
Source: livebench15 open models ranked+33 proprietaryData through Sep 2026
Open models ranked on LiveBench 2026 Long-Horizon
# shows rank among open models / rank overall (including proprietary).
| # | Model | Score | VRAM @ Q4 |
|---|---|---|---|
| 1 / 17 | MiMo V2.6 Pro RL · 1020B | 47.5 | ~613 GB |
| 2 / 19 | DeepSeek V4.1 Flash · 763.2B | 43.8 | ~458 GB |
| 3 / 20 | Kimi K3 · 2779.9B | 42.8 | ~1674 GB |
| 4 / 25 | DeepSeek V4 Flash Vision Exp · 304.6B | 39.0 | ~183 GB |
| 5 / 27 | GLM 5.3 · 753.3B | 35.9 | ~456 GB |
| 6 / 30 | GLM 5.3 Flash · 321.3B | 28.4 | ~195 GB |
| 7 / 33 | Qwen3.8 27B · 27.8B | 27.9 | ~17 GB |
| 8 / 35 | Smaug Flash · 304.2B | 27.1 | ~609 GB |
| 9 / 39 | Muse Spark Open 816B A42B · 822.0B | 18.9 | ~543 GB |
| 10 / 41 | NVIDIA Nemotron 3.5 Super VL 120B A12B BF16 · 124.5B | 15.8 | ~82 GB |
| 11 / 42 | Inkling · 952.4B | 14.1 | ~572 GB |
| 12 / 43 | Gemma 4 31B IT · 31.3B | 13.3 | ~20 GB |
| 13 / 44 | MiniMax M3 · 427.0B | 12.4 | ~257 GB |
| 14 / 46 | NVIDIA Nemotron 3 Ultra 550B A55B BF16 · 560.5B | 11.2 | ~370 GB |
| 15 / 48 | NVIDIA Nemotron 3.5 Lightning 30B A3B BF16 · 31.6B | 8.3 | ~19 GB |
Score vs model size
Which models give the most quality for their size — the ones worth running locally.
- Qwen3.8 27B, 28B, score 27.9 — on the efficiency frontier (best score at its size or smaller).
- DeepSeek V4 Flash Vision Exp, 305B, score 39.0 — on the efficiency frontier (best score at its size or smaller).
- DeepSeek V4.1 Flash, 763B, score 43.8 — on the efficiency frontier (best score at its size or smaller).
- MiMo V2.6 Pro RL, 1T, score 47.5 — on the efficiency frontier (best score at its size or smaller).
LiveBench 2026 Long-Horizon: frequently asked questions
- What is the best open LLM on LiveBench 2026 Long-Horizon?
- MiMo V2.6 Pro RL is the top open model on LiveBench 2026 Long-Horizon, scoring 47.5. Among all models tested — including proprietary ones — it ranks #17. The top model overall is Claude Opus 5.5 (Anthropic) at 85.0.
- What's the best LiveBench 2026 Long-Horizon model you can run on a 24 GB GPU?
- Qwen3.8 27B is the highest-scoring open model that fits in 24 GB at 4-bit quantization (~17 GB), scoring 27.9 on LiveBench 2026 Long-Horizon.
- Can open models match proprietary models on LiveBench 2026 Long-Horizon?
- Not quite on LiveBench 2026 Long-Horizon: the strongest proprietary model (Claude Opus 5.5) scores 85.0, ahead of the best open model (MiMo V2.6 Pro RL) at 47.5 — but you can run the open one yourself.
Scores aggregated from livebench. llmrun does not run this benchmark — see the source for methodology, or the about benchmarks for what it measures.