ARM-based server CPUs are entering the data center market as a viable alternative to x86 architectures.

Arm Holdings, the Cambridge, UK-based fabless processor architecture company, has been making significant strides in the data center market. Several cloud providers, including AWS, are running Arm-based chips in their data centers, and Fujitsu's Fugaku supercomputer at a research center in Japan, powered by Arm CPUs in combination with GPU accelerators, won the title of the world's fastest supercomputer last year. In March, Arm announced Armv9, the next generation of Arm CPUs, which according to Arm will perform better than older models in areas like digital signal processing and machine learning and make Arm systems generally more robust and secure, all while consuming less power than processors from data center market leaders Intel and AMD. Meanwhile, Nvidia's $40 billion agreement to acquire Arm from SoftBank Group continues pending regulatory approvals, with Nvidia already staking much of its data center product roadmap on the Arm architecture, including its BlueField SmartNICs and its upcoming AI workload CPU codenamed "Grace."

Despite these developments, actual enterprise deployment of Arm servers in data centers and colocation facilities remains negligible. Zachary Smith, managing director of bare metal at Equinix, stated: "I think it's probably a pretty small fraction still. If you don't count people who have racked and stacked IBM mainframes and other things that are running on RISC architecture and whatnot, the primary workload is still x86. The deploy base over the past 15 to 20 years has just been so dominant x86 that if you would have walked in three or four years ago, you would have been hard pressed to find AMD, although that's changed dramatically in the past three or four years." Industry sources agree that x86 architecture continues to dominate, though Arm adoption is on the uptick.

The largest cloud providers are increasingly embracing Arm, primarily through SmartNICs for network processing offload. According to Vlad Galabov, head of the Cloud and Data Center Research Practice at Omdia, "Today probably the biggest usage of Arm-based processors is in Ethernet adapters or SmartNICs, and it just so happens that the cloud service providers have led the adoption of this. This enables network protocols, storage protocols, or any type of SDM features to be run on the Arm processor that's on the Ethernet adapter. That just means that the CPU doesn't need to run the protocol, so it alleviates the CPU and it also makes data transfer faster." However, cloud providers are beginning to offer Arm servers directly to customers, with AWS offering Graviton2, Chinese CSPs offering Huawei solutions, and Ampere shipping for revenue since the second half of last year, while Oracle Cloud and Alibaba Cloud, which made Ampere Altra available, have also begun offering Arm instances.

Jeff Wittich, chief product officer at Ampere, explained the recent momentum: "I would say right now we're just at the beginning. If I go back three years or so, you could fairly say there was zero Arm in the data center." He attributed this change to two key factors: improved Arm core performance and a mature software ecosystem. "Over the last two years, a couple things have obviously changed. The performance of the Arm cores has dramatically improved, that's one thing. Secondly, when you look at what people like Ampere have done with the cores, I think we've finally been able to build an SOC around them that actually does perform for the data center, that acts the way you would expect a server to act, and can connect up to all the devices you'd expect to connect up to, such as the data center's accelerators and smart NICs. The other thing is that the software ecosystem is there now. It was a fair question two or three years ago to ask whether anything really ran. A lot of things ran, but there were some holes." Wittich predicted further movement: "I think you're going to see a couple more big hyperscale CSPs make some announcements this year and bring some things to market. All of the big infrastructure and service providers [will] have their own Arm-based instances." Major Linux server distributions now support Arm, solidifying the foundation for broader adoption.