Qualcomm is one of Arm’s biggest customers so, by taking a stake in Arm’s biggest rival, it is signalling a possible switch of allegiance.

“Qualcomm Ventures invests in innovative technology companies that have the potential to transform industries.” said Quinn Li, svp Qualcomm Technologies and head of Qualcomm Ventures, “SiFive has established itself as a leader in the RISC-V space making significant contributions to the broader semiconductor industry through its unique design methodology. We are excited to invest in SiFive to bring the potential of RISC-V to wireless and mobile.”

SiFive has now raised $125 million with Intel and Samsung among its investors.

SiFive says that six of the top ten chip companies are its customers. It says it has sold more than 100 licences for its RISC-V processors.

According to SFive CEO Naveed Sherwani, some of his IoT customers are saying RISC-V uses a tenth the power of Arm.

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