Tencent scales Hy4 to 770B parameters with 1M context window
Source published ·Modelwire updated
Original coverage: Simon Willison ↗·How Modelwire adds context
The development
Tencent's Hy4 preview marks a significant scaling milestone for open-weight LLMs outside the US frontier labs. The 770B parameter model with 49B active parameters and 1M token context represents a 2.6x parameter increase from Hy3 in just one month, signaling aggressive competitive momentum in the open-weight space. The model's architecture choices, particularly the mixture-of-experts design and expanded context window, suggest Tencent is targeting both capability parity and practical deployment advantages. For practitioners, this expands the viable open-weight options for production workloads where licensing or API dependency poses friction.
Modelwire’s AI-generated summary of coverage from Simon Willison.
Modelwire analysis
Analyst takeOur AI-generated reading of the wider context and the next developments to watch.
The one-month cadence between Hy3 and Hy4 is the detail worth sitting with. That pace implies either a pre-staged release pipeline or a training infrastructure operating at a scale most open-weight labs cannot match, and either interpretation says something meaningful about Tencent's organizational posture toward this effort.
Modelwire has no prior coverage to anchor this to directly, so the honest framing is that this story belongs to a broader pattern playing out largely outside our archive: the rapid compression of the gap between closed-API frontier models and openly licensed alternatives. Tencent's move here is best understood alongside the general trajectory of Qwen, DeepSeek, and similar Chinese lab releases over the past year, where successive generations have arrived faster and at larger scale than Western observers initially projected.
Watch whether independent evaluators reproduce Hy4's reported capability gains on benchmarks not included in Tencent's own release materials within the next four to six weeks. If third-party results diverge significantly downward, the aggressive release cadence starts to look more like positioning than validated progress.
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MentionsTencent · Hy4 · Hy3 · Simon Willison
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Modelwire summarizes, we don’t republish. Simon Willison originally reported this story as “Introducing Hy4 Preview”. The full content lives on simonwillison.net. If you’re a publisher and want a different summarization policy for your work, see our takedown page.