Google is using the RISC-V-based SiFive Intelligence X280 processor in combination with the Google TPU, as part of its portfolio of AI chips.
Fabless chip designer SiFive said that it was also being used by NASA, Tenstorrent, Renesas, Microchip, Kinara, and others.
RISC-V is an open standard instruction set architecture based on established RISC principles, which is provided under open source licenses that do not require fees.