AI-rewritten: This is a summary of an article from Ars Technica, rewritten by AI (Qwen, running locally) to make it easier to read. The facts come from the original article – read it for the full story.

---

The Museo de Historia de la Computación in Spain has unveiled a 1:1 scale visual replica of the famous Cray-1 supercomputer from 1976. Instead of using expensive, cutting-edge technology, the creative team powered the project with 30 Mac Minis from 2012. Developed over 18 months, this setup serves as a 50th-anniversary tribute to both the Cray-1 and Apple’s founding. In their most recent tests, the developers orchestrated the 64 active processing cores into a combined 1.3 teraflops of performance. Previously, the museum reportedly achieved 1.5 teraflops using all 70 available cores before one node went offline. Benchmarks were obtained using a custom matrix-multiplication Python script. Five PCs are quad-core i7s, and the remaining 25 are dual-core i5 models, with most dating to 2012 except for two units from 2014.

The replica helps visitors understand shifts in computer architecture since 1976. The original Cray-1 used vector processing, applying a single instruction to multiple data elements simultaneously, whereas the replica distributes work across independent processors in a parallel cluster. The peak theoretical performance of the original Cray-1 was approximately 160 megaflops. To manage the system, the team chose macOS Mojave (10.14) over Linux because it harnesses built-in support for MPI (Message Passing Interface), the software layer that allows all nodes to pass tasks to one another. Guests can watch in real time as the system runs matrix algorithms, mapping performance from a single core to the full suite running in parallel.

Combining 30 consumer PCs into an operational cluster presented engineering challenges regarding noise. The museum team used passive convection cooling via a steel rack chassis and aluminum tray mounts for each Mac Mini. The secret to near-silence comes from vertical mounting, which allows the tower to act as a natural thermal chimney where hot air rises through the structure without added mechanical fans. According to the museum, the only noticeable noise inside the replica comes from two gigabit Ethernet switches at the base that register between 30–33 decibels. Each individual PC is stated to produce 12–15 dBA of noise at idle. To manage this quiet giant, designers built a custom terminal that looks like a Cold War control room, incorporating elements of DEC VT05 and Processor Technology Sol-20 Terminal Computer designs from the 1970s.