Kimi K3 Max vs GPT-5.6 Sol Max: A Routing Problem in Coding
On July 23, zainhas released an in-depth analysis comparing Kimi K3 Max and GPT-5.6 Sol Max on software engineering tasks. The core conclusion is that the two models are not simply a matter of overall superiority, but rather have distinct specialties in different sub-domains, failure modes, and cost-effectiveness, making them suitable for combined use via routing strategies.
Confirmed
In benchmark tests across 8 categories of programming tasks, GPT-5.6 Sol leads in 5 areas and achieved a record single-pass reliability of 84.5%. However, when multiple attempts are allowed (e.g., pass@k), Kimi K3 Max, despite lagging in pass@1, achieves a higher performance ceiling with a peak pass rate of 89.4%, ultimately surpassing Sol Max in software engineering tasks. Economically, Kimi K3 Max costs $4.65 per rollout. Although slower than Sol Max ($8.37 per rollout), it achieves very similar results at roughly 55% of the cost.
Failure Modes and Routing Strategy
Beyond benchmark scores, zainhas broke down their failure types. Kimi K3 is generally closer to the correct answer but often narrowly fails to pass all tests; in contrast, GPT-5.6 Sol is more likely to break existing baseline tests when it fails. Benchmark data shows the correlation between Kimi K3 and Sol 4.6 on tasks is only 0.46, indicating highly complementary strengths rather than overlapping capabilities. Because of this, zainhas argues this is fundamentally a "routing problem." By using a cascade strategy—starting with Kimi K3 and escalating to Sol only if a verifier detects a failure—the solve rate increases to 85.6% (at about $7.30 per task), while theoretically, routing or cascading the two could cover 95.6% of tasks.
2026-07-23 ~ 2026-07-24 · 10 related posts
Primary sources
- [source] Kimi K3 max vs. GPT-5.6 Sol max looks like a routing problem, not a winner-take-all race — zainhas · 2026-07-23
- [source] Kimi K3 Max trails on pass@1 but beats Sol Max at pass@4 on SWE tasks — zainhas · 2026-07-23
- Kimi K3 costs $4.65 per rollout but takes 66 minutes versus Sol’s 17 — zainhas · 2026-07-23
- Sol hits 84.5% reliability as Kimi peaks at 89.4% on the same benchmark — zainhas · 2026-07-23
- [source] Kimi K3 and Sol 4.6 show low correlation and cover 95.6% together — zainhas · 2026-07-23
- Kimi K3 and GPT-5.6 Sol split 5 of 8 software-engineering domains — zainhas · 2026-07-23
- Kimi K3 misses more softly, while GPT-5.6 Sol breaks baselines more often — zainhas · 2026-07-23
- Kimi K3 Max matches GPT 5.6 Sol Max at 55% of the price — zainhas · 2026-07-23
- Kimi K3 plus Sol routing lifts solve rate to 85.6% at $7.30 per task — zainhas · 2026-07-23
- Kimi K3 Max matches GPT 5.6 Sol Max on software tasks at 55% of the price — togethercompute · 2026-07-24