Supercomputers can be measured in several ways, but the most essential statistic is their ability to perform floating-point operations per second, or flops. The fastest flop is what guarantees success. At its peak, Sierra could achieve 94.64 petaflops – 94.64 quadrillion floating-point operations – per second. El Capitan, at 1,809 exaflops, is about 19 times faster. At the end of 2025, it was officially recognized as the fastest supercomputer in the world. Neely says Sierra’s juice was no longer worth the squeeze.
It wasn’t a substantial red button, without the giant lever that turned the Sierra off. Sure, someone could have just cut the wires, but that’s not a recommended procedure. First, scientists using Sierra were warned by email to save their work. The DNR was then formally established – with no up-to-date parts.
The decommissioning was done in stages, starting with the compute nodes and switches in the rack, and lastly the management nodes because they are needed until the end. This process involves running scripts that digitally turn off the computer and then also turn off the demanding power switches. Dehydration also occurs. It could have been very heated when Sierra was alive, so the lab recirculated thousands of gallons of water per minute through sinewy pipes extending from beneath her floorboards. As she approached death, this water had to be drained. It was first tested by safety personnel to ensure it had an environmentally fit pH.