World’s fastest supercomputer up and running to secure US nuclear stockpile

“El Capitan” is the world’s fastest supercomputer and the third exascale computer on the planet.

The world’s fastest supercomputer was officially launched at Lawrence Livermore National Laboratory (LNNL) in California in January 2025.

The $600 million supercomputer was built to take care of classified tasks, including the simulation of nuclear testing. This replaces the underground testing of nuclear weapons, which was restricted in 1992.

Nevertheless, the US nuclear weapons stockpile still needs regular testing to ensure that it works properly. This can only be done through simulation, which is now possible with the help of the supercomputer.

Construction of the machine began in May 2023, and in November 2024, El Capitan went online. It’s now the world’s fastest supercomputer, performing 1.742 exaFLOPS, or a quintillion (18 zeros) calculations per second. It is capable of reaching a peak performance of 2.746 exaFLOPS.

In comparison, the best laptops for coding and programming usually deliver several hundred gigaFLOPS of power, or a trillion FLOPS.

El Capitan is also the third computer to reach exascale computing speeds. Before El Capitan, the first fastest supercomputer was the Frontier, found at Oak Ridge National Laboratory in Illinois.

The Frontier supercomputer performs 1.353 exaFLOPS of power with a peak of 2.056 exaFLOPS.

El Capitan was created to replace Sierra, which has been used since 2018. According to the Top500 rankings, Sierra is now the 14th most powerful supercomputer worldwide.