Report: Arm developing custom CPU for OpenAI's in-house accelerator — core IP would underpin 10GW of installed AI capacity

OpenAI is reportedly working with SoftBank-owned Arm on a new CPU to complement the custom AI accelerator it is co-developing with Broadcom. The collaboration, first reported by The Information, would see Arm design a server-class CPU that anchors OpenAI’s next-generation AI racks, potentially representing one of Arm’s biggest steps into the data center market to date.

The chip in question is OpenAI’s in-house AI accelerator, part of plans announced on October 13 to deploy custom AI accelerators and rack systems in collaboration with Broadcom. The SoC, specialized for inference workloads, is expected to enter production in late 2026 and scale up to support roughly 10 gigawatts of compute capacity between 2026 and 2029. The Broadcom accelerator, said to be fabricated by TSMC, has been in development for roughly 18 months.

According to The Information, Arm’s new role goes well beyond supplying architectural blueprints. The company has recently started designing and manufacturing its own CPUs rather than just licensing cores to partners, and sees the OpenAI contract as a chance to expand its server ambitions. People familiar with the discussions told the outlet that OpenAI could use the Arm-designed CPU not only with its Broadcom chip, but also with systems from Nvidia and AMD.

The potential revenue from OpenAI’s CPU program could reach into the billions, the report also said, representing a major windfall for SoftBank, which owns nearly 90% of Arm and has borrowed heavily against its stake. SoftBank has also pledged to invest tens of billions of dollars into OpenAI’s data center build-out and to buy AI technology from the startup to help accelerate Arm’s own chip development cycle.

Together with earlier agreements with Nvidia and AMD, OpenAI says its chip programs now total as much as 26GW of planned data center capacity. If successful, OpenAI’s custom chip deployments could reach a total installed base that analysts estimate could cost more than $1 trillion in construction and equipment in tandem with its Nvidia and AMD purchases.

The OpenAI–Broadcom chip could also give the ChatGPT developer more leverage in pricing talks with Nvidia, whose H100 and forthcoming Blackwell GPUs still dominate the AI training market. If Broadcom and TSMC can scale production, OpenAI’s inference chips may offer a partial hedge against the tight GPU supply that has constrained AI labs for much of the past year.

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