Inside OpenAI's Post-Astra Model Pipeline: From Rumors to Clues

Episode 1 · OpenAI's future model 'Bel' reportedly finishes pretraining in August (2026-08-28, 2 posts)

OpenAI has run unusually heavy pretraining since late 2025; a leak claims Sol finished in March, Astra in April/May, and the mysterious long-term model 'Bel' completed pretraining in August.

• OpenAI reportedly running many pre-trains; far-future model codenamed 'Bel' — haider1 · 2026-08-28
• Rumor: OpenAI's "Bel" model finished pre-training in August — haider1 · 2026-08-29

Episode 2 · OpenAI's Next-Gen Model Astra Reportedly Trained on Over 100K GPUs (2026-09-02, 10 posts)

OpenAI's next-generation model, internally codenamed Astra, has reportedly completed training at the Stargate site in Abilene, Texas, using over 100,000 GPUs across roughly two months of pretraining — a run Emad Mostaque reshared claims will be the first billion-dollar training run. Blogger imjustnewatai says Sam Altman confirmed the training is done and that Astra is OpenAI's first model significantly supervised by a previous-generation model during training. None of this is officially confirmed.

Confirmed

• The Information reports OpenAI considered naming Astra 'GPT-6' but dropped the idea (m3, m10); m6 adds the name may narrow to 'GPT-5.7 Astra' or 'GPT-Astra', saving the true generational leap for a later codename Bel
• Multiple posts (m2, m7, m9) agree on the scale: 100K+ GPUs, OpenAI's largest training run to date
• Internal tester Lentils80 (relayed by @OkDisplay3159, m1) disclosed two checkpoints: ultima-alpha, a likely public release candidate, and vega-alpha, a cybersecurity-focused enterprise version

Unconfirmed

• op7418 claims Astra is already deployed but not yet open, will offer 100% capacity to all paying users including Plus, with rollover reset credits — unverified
• Long-horizon task demos (8-day runs, 1,600 sub-agents, a Xiaomi 17 Ultra case) come from secondhand accounts
• haider1's claims of 10 research-level math/CS advances and OpenAI internal research-intern benchmark parity are opinion plus rumor; the $1B cost figure lacks an official source

Why it matters

• If the 100K-GPU, $1B scale holds, Astra marks a new order of magnitude in training cost and validates Stargate's role
• The old-model-supervises-training paradigm, if confirmed, would be a new scaling approach
• Dropping the GPT-6 name shows naming itself has become part of OpenAI's expectation management
• maksymandr's PostTrainBench Lite results look impressive but await independent verification

• OpenAI reportedly passed on the GPT-6 name for Astra, saving the 6-worthy jump for Bel — Angaisb_ · 2026-09-02
• Astra hailed as a watershed model, reportedly passing OpenAI's internal AI-research intern benchmark — haider1 · 2026-09-03
• Insider leak: OpenAI's Astra tested as 'ultima-alpha' and 'vega-alpha' checkpoints — Ok_Display_3159 · 2026-09-03
• OpenAI considered naming Astra 'GPT-6' but passed, The Information reports — rohanpaul_ai · 2026-09-04
• OpenAI weighed the 'GPT-6' name for Astra before dropping it, says The Information — rohanpaul_ai · 2026-09-04
• GPT-6 Astra scores impressively on PostTrainBench Lite benchmark — maksym_andr · 2026-09-04
• Leak claims GPT-6 Astra trained on 100,000+ GPUs at OpenAI's Stargate site — BLUECOW009 · 2026-09-04
• Astra reportedly trained on 100k GPUs at Stargate Texas in first $1B training run — ai · 2026-09-04
• Leaked GPT-6 Astra demo shows 8-day task runs, 1600 sub-agents, and 3D modeling — op7418 · 2026-09-04
• OpenAI "gpt-next" Leak: Astra Trained on 100k GPUs With Old Models Supervising — imjustnewatai · 2026-09-04

Episode 3 · OpenAI Researcher Says GPT-6 Astra Will Be Obsolete in Weeks (2026-09-04, 4 posts)

On September 4, OpenAI researcher roon said on X that the newly released GPT-6 Astra will be "obsolete" within weeks. The remark was widely relayed and seen as a rare candid statement from an OpenAI insider about the pace of model iteration—given how fast R&D is moving, any flagship release may only be a fleeting milestone. Several bloggers went further: the comment adds plausibility to earlier rumors of "a new round of large-scale pretraining at OpenAI" and "a new 10T-parameter model," suggesting OpenAI may have another, bigger flagship model held back for later this year; @markk even speculated about moves such as Grok 4.7 from competitors based on this. OpenAI has not officially responded or confirmed anything. Confirmed

• roon himself posted on X the remark that Astra would be "obsolete within weeks" (relayed by @Tolopono and others with consistent content).
• The remark continues roon's long-held view that "the pace of model iteration outstrips any current release."

Unconfirmed

• The existence of a "10T new pre-trained model" and any release date this year are rumors with no official evidence.
• Relay posts differ on Astra's ownership: most refer to OpenAI's GPT-6 Astra, while the conversation version relayed by @UltraRareAF refers to Google's Astra—a factual discrepancy that remains to be verified.
• @markk's inference that Grok 4.7 is coming is personal speculation.

Why it matters

• An internal researcher publicly downplaying the company's latest flagship may signal a more aggressive release cadence and reflects the frontier-lab norm of "obsolete upon release," which is relevant to model procurement and product planning.

• OpenAI researcher roon says GPT-6 Astra will be obsolete within weeks — Tolopono · 2026-09-04
• OpenAI Researcher roon: GPT-6 Astra Will Be Obsolete in Weeks — Tolopono · 2026-09-04
• OpenAI Employee Hints Astra May Be Obsolete in Weeks, Fueling New Big Model Rumors — haider1 · 2026-09-04
• Rumor: OpenAI employee hints major new model coming, Astra possibly obsolete within weeks — mark_k · 2026-09-04

Episode 4 · OpenAI says Navier-Stokes proof used a next-gen model far stronger than GPT-6 Astra (2026-09-09, 6 posts)

According to Axios, the model OpenAI used to claim a solution to the Navier–Stokes Millennium Prize Problem was an internal model "significantly stronger than GPT-6 Astra," not the publicly released Astra. Omar Sanseviero of dair-ai relayed the official statement that the proof was produced by a set of agents using OpenAI's next-generation model. This means an unreleased next-gen model sits behind the Millennium Problem claim, and the Astra the public sees is not OpenAI's capability ceiling.

Confirmed

• Axios reported that the model OpenAI used to solve the Navier–Stokes problem is significantly more capable than the public GPT-6 Astra.
• OpenAI's official wording: the proof was completed by a set of agents using its next-generation model, which is significantly stronger than GPT-6 Astra.

Why It Matters

• kimmonismus noted it's long been no secret that OpenAI holds internal models stronger than public ones, but the official phrasing "significantly stronger" is still remarkably bold.
• rohanpaulai commented that models used inside OpenAI Frontier Labs are far more advanced than what the public can access, estimated to be more than a year ahead.
• This means public benchmarks and external APIs may systematically underestimate the true frontier level of OpenAI's labs.

• Report: OpenAI's Millennium Problem model is internal, "significantly more capable than GPT-6 Astra" — kimmonismus · 2026-09-09
• "Significantly more capable than GPT-6 Astra": OpenAI's internal model gap — kimmonismus · 2026-09-09
• dair-ai amplifies OpenAI's next-gen model claim behind Navier-Stokes solution — dair_ai · 2026-09-09
• Commentary Claims OpenAI Frontier Labs Run Models a Year Ahead of the Public — rohanpaul_ai · 2026-09-09
• OpenAI used a model 'significantly more capable' than Astra for Navier-Stokes, per Axios — 141_1337 · 2026-09-09
• OpenAI Quietly Discloses a Model Far Beyond GPT-6 Astra, Released Just 4 Days Ago — MatthewBerman · 2026-09-09

Episode 5 · Engineer Speculates OpenAI Has Started GPT-6.5 Pretraining, Beating Astra (2026-09-09, 2 posts)

OpenAI engineer willdepue speculates the company has begun pretraining astra-next/GPT-6.5, which already outperforms Astra in evals. Some suggest it may be a math-focused pretraining run.

• OpenAI May Already Be Pretraining GPT-6.5 That Beats Astra on Evals — willdepue · 2026-09-09
• Speculation swirls: OpenAI's mystery model may be math-specialized pretraining beating GPT-6 Astra — giffmana · 2026-09-09