It's not Xgrid, but a computing museum in Spain has recreated a Cray-1 supercomputer to a 1:1 scale, using a total of 30 Intel Mac minis to generate up to 1.5 teraflops of performance.
Sometimes, efforts to recreate famous old computer systems involve the use of more modern parts. In the case of one exhibit from the Museo de Historia de la Computacion in Spain, it's a visual replica of the Cray-1 supercomputer, but with it relying on the power of out-of-date Mac minis.
The replica, first reported by Ars-Technica is both a celebration of the 50th anniversary of the Cray-1, as well as that of Apple's founding. Matching the styling of the original Cray-1, it's a tower of vertically-mounted Mac minis behind green and clear glass.
The project that took 18 months to make.
The report does make the odd statement that using Intel-era Mac minis may not seem like "the obvious first choice" for making a cluster supercomputer. Technically, they aren't the first choice, but in 2026, it may be a cost-effective one.
A vast amount of computing devices could be used for cluster computing, even a bunch of Raspberry Pis, so using Mac minis isn't that far-fetched.
It is probable that, as an organization that calls out for old hardware donations, it had a lot of old Intel Mac minis on hand. The transition to Apple Silicon meant a lot of Mac minis had to go somewhere.
The current Mac mini is still being used for cluster computing, with modern applications revolving around AI workloads.
A stack of minis
The Cray-1 replica is made from a collection of 30 Mac minis, with most dating back to the SSD- and RAM-upgradable 2012 model. There is a total of 64 processing cores, consisting of 25 dual-core i5 models and five with quad-core i7 chips.
Rather than using Linux, the replica uses macOS Mojave 10.14, with Message Passing Interface (MPI) support used for the nodes to communicate with each other.
There is a difference in terms of how the system works, too. Though the original used vector processing to send a single instruction to multiple elements at the same time, the replica instead uses independent processors in a parallel cluster.
Performance is also up considerably in the remake. The original Cray-1 was capable of 160 megaflops of performance, while the new version gets 1.3 teraflops on average.
Though it is capable of more work than the computer its emulating, the remake hasn't quite reached its full potential. It's only about half full.
The team has run a crowdfunding campaign to get between 70 and 80 more M4 Mac minis to fill the other half of the tower. If successful, the museum hopes to reach the Top500 supercomputer list.
Cool and quiet
Despite being a collection of Mac minis working on concert, there's not much noise from the entire setup.
The construction has Mac minis connected to the steel rack vertically with aluminum mounts. The bases of each Mac mini have been removed to help with passive cooling instead of relying on active cooling..
Not only are the aluminum chassis helping through thermal conduction, but the vertical orientation acts as a chimney, like it did with the Cray-1 original hardware. Cool air enters from the base of the tower, rising through and cooling nodes before escaping through the top.
And, it's not that loud. The replica measures between 30 and 33 decibels, mostly because of sound isolation of the tower. That is only because the noisiest parts are the two gigabit Ethernet switches at the base, which the team seeks to switch out.
Terminal - Image Credit: Museo de Historia de la Computacion/Facebook
While the main draw is the Cray-1 tower itself, users will see the results at a specially designed terminal. Resembling those used to manage supercomputers in the 1970's, the terminal will gain other elements to add to the visual aesthetic, including 3.5-inch and 5.25-inch floppy drives and a keyboard shell.
That terminal is also capable of controlling a pair of 2004 Cray C1X supercomputers that are also in the museum's collection.
The Museo de Historia de la Computacion is located at Camino de Toril, Majadas, Spain. If you happen to be near it, the museum is open to the public on Saturdays for guided tours.
