Can Grok 4.5 Undercut Claude Opus On Price And Speed?

Elon Musk said SpaceX will open its Grok 4.5 model to the public Thursday, calling the 1.5 trillion-parameter system an Opus-class rival that is faster and cheaper.

Grok 4.5 Reaches Public Release

Musk said on X that the public release would arrive a day later, ending weeks of leaks and speculation about the flagship model. He billed it as an Opus-level system, faster and more token-efficient than Anthropic's top model, and available at a lower price. Beta users gave positive early feedback, he said, which drove the decision to widen access.

The model runs on a fresh 1.5 trillion-parameter V9 foundation, about three times the size of the base behind earlier Grok versions and tuned for Nvidia's newest chips. It entered private beta at SpaceX and Tesla on Jun. 28, with Cursor coding data folded into its supplemental training.

Musk folded xAI into SpaceX this year and rebranded the unit SpaceXAI, consolidating his compute and capital under one roof. The company shipped the prior version, Grok 4.3, in Apr., and had teased its successor for weeks. He has also promised a model trained from scratch every month through the end of 2026, an unusually aggressive pace for foundation systems.

Also Read: SpaceXAI Wants A Cursor-Powered Claude Killer Before The $60B Deal Even Closes

GPT-5.6 Launch Sets Up Showdown

OpenAI previewed its GPT-5.6 family in late June but held it back for a small circle of vetted partners. It limited that early access to about 20 organizations, a staggered rollout it arranged after sharing the models with the U.S. government.

On Wednesday the company confirmed that its Sol, Terra and Luna models would reach the public Thursday, the same day as Grok 4.5. Sol anchors the lineup as the flagship, Terra targets everyday business tasks, and Luna handles lighter work at the lowest cost. Sam Altman has defended the gradual approach as reasonable for increasingly capable systems, while conceding it is not the process he sees as ideal.

The paired launches put the two companies head-to-head, shifting the contest from early previews to real-world results across coding and reasoning tasks. Independent benchmarks for Grok 4.5 do not yet exist, which leaves Musk's Opus comparison unverified beyond the internal tests at SpaceX and Tesla.

Musk And Altman Feud Resurfaces

The showdown revives a feud that predates both models. Musk helped found OpenAI in 2015 as a nonprofit and left its board three years later after clashing over control. He sued OpenAI and Altman in 2024 over a pledge to run the venture as a nonprofit, though a jury dismissed the case in May as untimely.

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