Actually, no, that's wrong: Tesla benchmarked actual AutoPilot neural networks on old and new hardware, using field test units of the Tesla AI Chip. Also, it's not just Elon saying it, but also Pete Bannon who designed Apple's first 64-bit chip, among other chips. This is from the conference call transcript:
"Peter Bannon - Tesla, Inc.
My team is leading currently the Hardware 3 development. The chips are up and working, and we have drop-in replacements for S, X and 3, all have been driven in the field. 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 Andrej and his team will be able to do with this hardware in the future."
So the source of the 10-fold speedup claim is that
Tesla actually measured Tesla AI-chip performance on real, working hardware, and these numbers should be a
lot more accurate than any forward looking guesses made in the past about software that didn't exist yet.