All have failed, or are still trying. Computers dating back to the ABC, invented by Iowa State's John Atanasoff, perform their functions in sequence. That is, they perform an operation, get a result, perform another operation, get a new result and so on. In the early 1980s, the quest for faster high-level computers focused on design of parallel machines. In a dramatic departure in computing philosophy, parallel machines divide a large problem into smaller pieces, obtain answers to the smaller pieces, then combine the results into a final answer.
Parallel machines can perform billions of operations in a heartbeat.
Problems that take a serial computer weeks to solve now can be done in five minutes. The problem is, the programs that make computers work are written exclusively to run on serial machines. The proven code is written in serial. Literally trillions of dollars' worth of serial code still is being used by scientists. They use it to design airplanes and automobiles, to understand how a drug is metabolized in the body, to predict long-term climate patterns.