One of the more fascinating stories in the tech world this year has been Arm’s push to develop and sell its own server CPUs. The long-time IP and architecture vendor ruffled more than a few feathers with the announcement that it would be designing its own chips, but the die was cast long ago, as Arm has watched demand for Arm architecture server chips explode around it.
Arm’s first server chip will be the Arm AGI, which the IP designer turned chip designer announced back in March. AGI is not scheduled to enter volume production until later this year, but with the red-hot market for server CPUs right now, Arm’s Taiwanese partners have been eager to get the next era of Arm started. So when Patrick told me that he found out that ASRock Rack’s booth had an AGI server on display, visiting ASRock Rack quickly became mandatory.
ASRock 1U4E1S-ARM: One AGI CPU in 1U
While Arm’s first big (announced) direct customer is Meta, ASRock Rack is a launch supporter for Arm’s AGI CPU launch. The company announced a server design back in March alongside the AGI announcement with their dual node, 2OU 2OU2N-ARM server. That server will be equipped with two compute nodes, each powered by ASRock’s ARMD12M3 motherboard. The substantial 2OU server is not the only product ASRock is using that AGI motherboard in: it will also be going in a more petite 1U server. That brings us to the 1U4E1S-ARM.
This ASRock Rack 1U4E1S-ARM is, for all intents and purposes, half the density of ASRock’s larger 2U server, in half the size, going from two processors in 2U to one processor in 1U.
The star of the show here is, of course, the Arm AGI CPU. Fabbed on TSMC’s 3nm process, the CPU packs in 136 of Arm’s Neoverse V3 cores. Arm’s clockspeed targets are somewhat modest here, with the highest-clocked chip topping out at 3.7GHz, so it would be fair to say that the AGI is more geared towards higher-density CPU deployments than high-performance (low-core-count) configurations. The chips will run at a base TDP of 300W, which is similar to other contemporary server CPUs, perhaps even a bit lower.
Feeding Arm’s new server CPU cores are 12 channels of DDR5 memory, with a maximum clockspeed of DDR5-8800. Memory bandwidth and memory channels have become a new battlefront between server CPU vendors as an ever larger number of cores requires more bandwidth to feed them. All the while, agenetic AI workloads threaten to shift computing patterns towards more cores being more consistently busy. Motherboard vendors have their work cut out for them in routing all of those memory channels. In ASRock Rack’s case, they opted to keep things simple and skinny, with just 1 DIMM per channel, split between the left and right sides of the chip.
The AGI is also part of the first generation of server CPUs offering PCIe Gen6 connectivity, making PCIe lane routing, retiming, and reliability the other big challenge for motherboard vendors. The chip itself supports 96 lanes of the latest I/O standard. You can also run CXL 3.0 on top of that. Between drive bays and expansion cards, altogether the 1U4E1S-ARM will be exposing around 80 of those lanes.
On the expansion front, the server offers 1 full-height, full-length (FHFL) PCIe Gen6 x16 slot and 1 HHHL PCIe Gen6 x16/x8 slot. And that is it for PCIe cards. Meanwhile, another 16 lanes feed an OCP NIC 3.0 slot. We also spotted a couple of QSFP ports on ASRock Rack’s board, though it is not clear how those are configured or which controller is used to drive them in ASRock’s design.
As for storage, the server offers a couple of options. Towards the rear of the system, there are two M.2 slots for internal storage, and at the front of the system, there are four hot-swap E1.S bays, each rated to run at PCIe Gen5 x4 speeds.
Finally, powering the server are a pair of redundant 800 Watt 80 PLUS Titanium PSUs.
All told, the admittedly unfilled server looked quite spacious for the amount of hardware it packs inside. Since ASRock Rack designed these motherboards to be paired up, there is plenty of space in their first 1U Arm server.
At this point, ASRock is not releasing any further details on the server, and it has yet to even be listed on their website. With a motherboard design already in hand, presumably the company is largely waiting on TSMC to ramp up production of the CPUs for Arm, at which point everything can properly kick off.
Final Words
While the showfloor of Computex is chock-full of servers, there are arguably as few that were as important to the future of the industry as the Arm AGI servers. The first generation of boxes based on Arm’s in-house CPU designs, the launch of the AGI marks a major shift in the relationship between Arm, its customers, and server buyers. The Arm architecture as a whole has carved out an ever-larger share of the server CPU market, and with servers such as the 1U4E1S-ARM, Arm is finally going to have the opportunity to take a piece of that market directly.
