John Chambers, the former CEO of Cisco, knows a lot about tech bubbles. As a veteran of the internet’s boom that led to the dot-com crash, he’s seen his fair share of transformative technologies, and their effects on the industry.

But the recent frenzy of AI-fueled investments and stock-market gains has Chambers experiencing déjà vu: The AI-hype feels all too reminiscent of the 1990s crash.

“In the internet age, there was an irrational exuberance on a really large scale,” Chambers told the Associated Press. “In this AI one, there is a lot of tremendous optimism that does indicate a future bubble for certain companies.”

“Is there going to be a train wreck? Yes—for those that aren’t able to translate the technology into a sustainable competitive advantage,” he added.

The speed of AI