HP figured the Machine would replace data server farms with a computer the size of refrigerator using a fraction of the power. To do that, it would compute using specialized core clusters, photonic circuits and a huge pool of unified memory. For the latter, it depended heavily on the memristors -- which store data with no power -- and company researchers insisted that any other technology just wouldn't do. It has scaled that ambition back, however, and chief technology officer Martin Fink now says that for now, it'll be a "memory-driven" Linux computer based on DRAM. "We way over-associated this with the memristor," he told the New York Times.

Mechanical mockup of new 'node board' for HP's Machine

Running the Machine on DRAM would make it impractical, but HP says it would still be a radical shift from computers today with a whopping 320TB of memory. The idea is to develop a RAM-based prototype to attract developers to the technology, then introduce a version with phase change memory later. The final product would run on memristors once they're market-ready.

HP -- which recently split its business and consumer divisions -- is betting big on The Machine tech and plans on investing a half a billion dollars in it. The company thinks it could eventually be shrunk to smartphone size, giving users Google Now-like AI capability without external servers. Researchers have already shown that similar technology using can already perform chores like image recognition. But critics wonder how much of a game-changer the Machine can be without memristors, and HP itself has now stopped making any predictions as to when it'll finally arrive.