Rambus claims Infineon is violating its patents on two kinds of computer memory, known as synchronous dynamic random access memory (SDRAM), and Double-Data Rate DRAM (DDR).

FORBES: Rambus Patent Army Marches On

Everspin makes a type called MRAM (magnetoresistive random access memory), which uses magnetic properties to store data.

BBC: ReRAM competes to be tech's next memory chip standard

And AgigA Tech makes so-called non-volatile Random Access Memory (RAM) that helps people store and retrieve rapidly changing data far more quickly than the slow-poke disk drive technology that keeps data centers humming.

FORBES: AgigA Tech's Fast, Battery-Free Data Retrieval