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Apple eyes Nvidia NVLink to power its new custom M8 Ultra AI servers — historically bitter rivals reportedly team up for 2029 data center push
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Apple is reportedly developing AI servers based on its own M-series processors and is evaluating NVLink Fusion technology for interconnects, according to The Information. The machines are expected to use M8 Ultra processors and arrive in 2029, the report claims. For now, the usage of the NVLink Fusion platform is not formalized and has not been confirmed by either Apple or Nvidia, but if Apple decides to use it instead of competing solutions, this may have significantly broader market implications than just Apple using Nvidia hardware.
Apple is reportedly considering at least two server configurations: a smaller machine equipped with two M8 Ultra processors and a higher-end version featuring four M8 Ultra system-on-chips. Although Apple has its own UltraFusion technology for stitching two high-end SoCs together seamlessly, it looks like the company does not have a proper solution for scale-up and scale-out connectivity of its processors, which is where Nvidia's NVLink Fusion comes into play. Apparently, Apple wants to use NVLink infrastructure, which includes not only an interconnection protocol, but also switches, chiplets that add NVLink connectivity, and a software stack, for its servers. The project was reportedly initiated around a year ago and was backed by John Ternus while he headed Apple's hardware engineering organization.
Apple already builds custom servers for Private Cloud Compute, which handle AI workloads too demanding for local execution on iPhones and Macs, The Information claims. Most of these machines use Apple's internally developed connectivity technologies, which are reportedly too slow and costly for large-scale commercial deployments, which is why Apple is looking elsewhere.
The Information specifically mentions Apple's need for connectivity technology suitable for large-scale deployments, although it does not explain exactly what this means architecturally. If the publication is referring to connecting multiple servers into larger clusters, this would normally be the job of scale-out technologies such as Ethernet or InfiniBand, rather than a scale-up fabric such as NVLink. Nvidia originally developed its NVLink fabric technology to scale-up performance of its accelerators, so the technology is optimized for accelerator-to-accelerator connectivity and enables a rack of Nvidia GPUs to function as a tightly coupled compute domain. There is a different implementation called NVLink-C2C, which is a coherent chip-to-chip interface for connecting CPUs to accelerators and CPUs to CPUs
Meanwhile, modern Apple M Pro and M Ultra processors are system-in-packages consisting of a CPU chiplet and a GPU/neural engine chiplet, which are stitched together using TSMC's SoIC-mH technology. If Apple continues to use this architecture (very likely), an M8 Ultra processor can be considered as a CPU and an accelerator. However, this raises the question of how Apple intends to connect M8 Ultra processors to NVLink and which components of the SiP would participate in the NVLink domain. One possibility is that Apple could expose the accelerator portion of M8 Ultra to NVLink through an NVLink Fusion chiplet, which effectively means it will treat it as an accelerator for a scale-up domain. Another possibility is that Apple is developing a different accelerator architecture for its servers, perhaps by simply placing the GPU/NPU chiplet onto a separate substrate/interposer and equipping it with its own memory, though there is currently no evidence that confirms such a design for a chip that is years away.
Another thing to keep in mind is that Apple is a member of the UALink Consortium, an organization overseeing development of industry-standard UALink accelerator-to-accelerator interconnections that supports up to 1,024 accelerators. While for now there is a limited choice of UALink switches, by 2029, there will be industry-s