What is the highest working frequency for SPI

Has anyone tested how fast SPI bus can go?

SPI0 & SPI1 (master mode only) works reliable with up to 40 MHz clock.
SPI2 (slave mode only) also works up to 40 MHz (tested mostly with maximal clock of 26 MHz).
SPI3 (connected to SPI Flash) should work up to 100 MHz, I’ve tested only with maximal clock od 83 MHz).

Tested with K210 <-> K210, K210 <-> ESP32 and K210 <-> STM32F4.