Tesla’s in-house chip is 21 times faster than the older Nvidia model Tesla used. And each car’s computer has two for safety.
There’s redundancy in the chips’ power supplies and data input feeds, too. Even the car’s cameras are on two separate power supplies to guard against failures.
Each chip makes its own assessment of what the car should do next. The computer compares the two assessments, and if the chips agree, the car takes the action. If the chips disagree, the car just throws away that frame of video data and tries again,