Sparse MoE plus speculation: open models beat closed on speed

StepFun (阶跃星辰) released Step-3.7-Flash on June 4, the first open-source model whose inference speed surpasses closed-source alternatives. The combination of sparse MoE activation and aggressive speculative decoding puts Step-3.7-Flash at 3-5× the inference speed of comparable closed-source models at similar quality, marking a watershed for the "open-source can be faster than closed-source" narrative.