Kimi K3.1 launch: Sonnet 5.5 plus DeepSeek V4.1 Flash wins on cost per task
The author calls Kimi K3.1 the top open-weight model but behind Opus 5.5, and says a Sonnet 5.5 plus DeepSeek V4.1 Flash combo dominates it on performance versus cost per task.
Kimi K3.1 is out; it is the #1 OSS model. It places similarly to Opus 5, which was released 3 months ago. Thus, China is lagging the frontier by about 3 months. The Kimi K3 release was #1 on Code Arena, at the time better than all US labs. K3.1 is close, but substantially off from Opus 5.5. On a performance vs cost-per-task basis, the combo of Sonnet 5.5 and DeepSeek V4.1 flash together dominate this model. The race is so tight!!! Congrats to the Moonshot team on a great release. And now, back to work. The frontier never sleeps!
This post quotes another post: x.com/arena/status/2113687344532320326