Google's next-gen Gemini 4 "Carbon" reportedly enters early testing with stronger 3D capabilities

Less than a month after Gemini 4's launch and just 8 days after Argon became fully available, Google is reportedly already testing its next-generation model codenamed Carbon. According to multiple leak posts, Carbon's Early Access Program (EAP) has officially kicked off—partners have received early access and the model has appeared in blind tests on LMArena, suggesting an official release is near.

Confirmed (per leak sources)

• User Lentils shared 3D generation outputs from the internal Gemini 4 checkpoint "Carbon," saying it is clearly better than the released Gemini 4 Argon at 3D generation, though still imperfect; one tester used Carbon to generate an entire game level.
• Carbon has entered closed testing: the EAP is live, partners have access, and it has surfaced on LMArena—per 新智元, the blind-test name still shows "gemini-4-argon," with testers identifying it by its noticeably slower responses.
• An earlier leak claimed Google was preparing two new models, Carbon and Argon, speculating that Carbon might be a smaller tier (Flash or Pro level) while Argon ties into Google's astra/fable projects; based on current materials, Argon is the released version and Carbon is the stronger new model.
• Google is reportedly prioritizing this work (mentioned by m3).

Not yet confirmed

• Google has not announced Carbon's positioning or release timing; the "smaller model" claim was early speculation and sits in tension with hands-on reports of "3D capability surpassing Argon"—official confirmation is needed.
• All information comes from anonymous leaks and tester accounts; Google has not responded officially.

Why it matters

• With next-gen testing leaks emerging barely a month after Gemini 4 shipped, if true it shows Google iterating at breakneck pace (新智元 describes the RSI treadmill accelerating), and 3D generation may become a key competitive capability in the next round of model wars.

2026-10-21 ~ 2026-10-22 · 5 related posts

• [source] Gemini 4 Carbon enters early access, spotted in LMArena, stronger at 3D than Argon — lyraxana · 2026-10-21
• Google reportedly prepping new Gemini models Carbon and Argon weeks after Gemini 4 — haider1 · 2026-10-21
• Gemini 4 Carbon reportedly in closed testing and already on LM Arena, release near — koltregaskes · 2026-10-22
• [source] Google's next flagship Carbon spotted in LMArena blind tests: stunning 3D, fixes Argon's laziness — 新智元 · 2026-10-22
• [source] Gemini 4 'Carbon' checkpoint leak shows notable 3D generation gains over Argon — lyraxana · 2026-10-22