Broadcom unveiled Thor Ultra, an 800G network interface card (NIC) capable of connecting more than 100,000 XPUs to large-scale AI clusters.

The NIC is Broadcom's answer to scaling bottlenecks, acting as a control point for managing congestion and maintaining reliability across increasingly larger AI clusters.

Broadcom’s new NIC is engineered for hyperscale deployments exceeding 100,000 XPUs, bringing full compliance with the Ultra Ethernet Consortium’s (UEC) specifications and introducing a new generation of advanced remote direct memory access (RDMA) features to boost efficiency across massive AI clusters.

“Thor Ultra is a breakthrough in AI networking,” Ram Velaga, SVP and GM of Broadcom’s Core Switching Group, claimed. “By introducing the first 800G NIC with full UEC feature compliance and advanced RDMA capabilities, we deliver the performance, scalability, and openness required for tomorrow’s scale-out AI clusters – without the lock-in and with true interoperability.”

Hasan Siraj, head of software products and ecosystem at Broadcom, revealed that Thor Ultra was developed in the pre-AI days, but now complements its recently unveiled Tomahawk 6 chip in building larger and more efficient AI fabrics.

“Tomahawk 6 lets customers stay within two tiers instead of three, which simplifies the network and cuts complexity,” Siraj told SDxCentral. “As clusters grow from 100,000 to half a million XPUs, the NIC becomes the control point for congestion control and reliability at scale.”

The chip giant has also re-engineered RDMA for AI workloads, adding features like packet-level multipathing, out-of-order data placement, hardware-based retransmissions, and programmable congestion control to prevent bottlenecks in scale-out environments.

Siraj said the additions aim to meet demands from AI clusters accelerating far beyond earlier size projections.

“We didn’t anticipate the scale growing this quickly,” Siraj admitted. “But we could tell the market was heading toward unprecedented scale, and that’s where the need for this NIC really comes in.”

Beyond performance, Thor Ultra also strengthens Broadcom’s platform-level security with line-rate encryption, secure boot, and firmware attestation via SPDM, allowing the host to verify the NIC’s integrity.

The NIC is available in chiplet, IP, or standard PCIe and OCP 3.0 card form factors. Siraj told SDxCentral that demand for the latter was growing among customers, but that board-based offerings were “50-50 split” between PCIe and OCP 3.0.

Thor Ultra is the latest in Broadcom’s Thor family of NICs, effectively doubling the performance of the 400G Ethernet NIC unveiled last May.

The 800G launch comes just a week after Broadcom unveiled Tomahawk 6 Davisson, its third-generation co-packaged optic (CPO) Ethernet switch that offers a staggering 102.4 Tb/s.

Thor Ultra is designed to complement Broadcom’s wider AI-focused hardware offerings, including Davisson, as well as the Tomahawk Ultra and Tomahawk 6, as the chip giant looks to provide an array of options for firms building large-scale AI clusters.

To validate its AI efforts, Broadcom was the chip designer chosen by OpenAI to help develop the startup’s long-teased custom hardware.

In a deal announced earlier this week, Broadcom will help OpenAI develop its own GPUs, with the ChatGPT maker also agreeing to leverage its networking solutions in its racks.