Tesla CEO Elon Musk said Wednesday that the company's custom-built chip for handling autonomous driving is nearly ready.

Tesla is one of a few automakers developing self-driving technology, but it stands apart because it's been developing its own silicon for performing artificial-intelligence computations, rather than continuing to rely on systems from ongoing chipmakers like Nvidia.

"Very importantly, the Tesla self-driving chip technology that we've been working on for three years is finally coming to fruition," Musk said on Tesla's second-quarter earnings call. Musk talked publicly about the chip for the first time in December at a company event.

Musk brought key people from the Autopilot self-driving team on the earnings call. One of them was director Pete Bannon, who came to Tesla in 2016 after nearly eight years at Apple following the PA Semi acquisition. Bannon said his team at Tesla is leading the development of the third development of the Autopilot hardware.

"The chips are up and working, and we have drop-in replacements for S, X and 3, all have been driven in the field," Bannon said. "They support the current networks running today in the car at full frame rates with a lot of idle cycles to spare. So I think we're all really excited about what Andre and his team will be able to do with this hardware in the future." Bannon was referring to Andrej Karpathy, Tesla's head of AI, who joined last year from OpenAI and previously worked as an intern at Alphabet's DeepMind unit. Another Alphabet subsidiary, self-driving group Waymo, uses Intel chips in its vehicles.

Bannon said that when he joined Tesla, employees considered many options, including Nvidia graphics cards, and said they talked with people at Arm, whose technology is used in chips from Qualcomm and other companies.

"Nobody was doing a bottoms-up design from scratch, which is what we elected to do," Bannon said.

Musk said Tesla plans to grow the chip team and invest in the technology as fast as possible.

Musk said it will cost the same amount as systems Tesla currently puts in its cars, but will bring much more processing power. Tesla vehicles have previously come with Nvidia components onboard.

Bannon's predecessor, former Apple chip architect Jim Keller, left Tesla in April, following a Tesla vehicle crash that involved Autopilot.

Correction: This story was revised to show that Andrej Karpathy joined Tesla from OpenAI, and correct the spelling of his name.