Hewlett-Packard scientists plan today to report advances in the design of memristors, a new class of devices capable of replacing transistors, using a vast three-dimensional array, which allows for ultradense computing devices.

HP now has working 3-nanometer memristors that can switch on and off in about a nanosecond. HP says it could have a competitor to flash memory in three years that would have a capacity of 20 gigabytes a square centimeter.

Memristor-based systems also hold out the prospect of fashioning analog computing systems that function like biological synapses in brains.