Jim Keller, something of a legend in the microprocessor industry, has suddenly resigned from Intel after just two years.

Jim Keller has a long history in the industry, having working for Digital Equipment Corp., AMD, Apple, Tesla and Intel. Wherever Keller has gone, he has often led the development of game-changing microprocessors for the company employing him.

During his first stint at AMD, in the late ‘90s, he worked on the K7 Athlon chips and led the development of the K8, AMD’s first 64-bit line of chips. He eventually found his way to P.A. Semi, the company focused on mobile processors, going to Apple shortly before it bought the firm.

During his time at Apple, Keller helped develop the A-series line of processors used in iPhones and iPads, and rumored to be coming to Macs.

In 2012, Keller returned to AMD, where he lead the development of the Zen families of chips, that helped the company gain ground on Intel for the first time in years.

After a brief stint at Tesla, where he designed the company’s autopilot chip, Keller took a job at Intel where he was believed to be working on helping the chip giant become competitive once again. Intel has had well-publicized struggles recently, with a Fortune profile piece saying the company was “betting its chips on microprocessor mastermind Jim Keller.”

Needless to say, his history of staying with a company until he helps it achieve a ground-breaking success makes his sudden departure from Intel all the more unusual. In the company’s announcement, Intel said Keller was leaving “due to personal reasons,” and wished “him and his family all the best for the future.”

AnandTech’s Dr. Ian Cutters did receive confirmation that Keller will remain a consultant for six months to help with the transition.

Whatever caused Keller to leave Intel, here’s to hoping all is well with him and his family, and that he continues to have as much influence on the industry as he has in the past.