https://wccftech.com/2020-ipad-pro-performance-betas-the-new-macbook-air-but-only-slightly-faster-than-2018-ipad-pro/

The new A12Z processor in 2020 iPad Pro is essentially the same as the A12X processor in its predecessor, however, it easily beats the new MacBook Air in benchmarks.

As per Geekbench benchmarks, the A12Z processor has the same clock speed and architecture as the A12X processor, with the exception of an additional GPU core. Therefore, the performance improvements can be considered negligible, but the 6GB RAM upgrade might be the differentiating factor. As we are on the verge of iPadOS 14 announcement in a few months, the additional amount of RAM might be more useful based on the new features that Apple releases in the software update.