According to the the latest RM0433, the STM32H7 SPI can be run in both master and slave mode up to kernel frequency / 2. You are allowed (in the Cube) to set the SPI kernel clock to 400 MHz, so this suggests an absolute maximum of 200 MHz. According to the latest STM32H743xI datasheet (October 2017, rev3) Electrical Characteristics, Table 102, SPI dynamic characteristics, for SPI 1-3 in slave receiver mode with Vdd in the 1.62-3.6V range, the maximum rate is 150 MHz and in Master Transmit mode for Vdd in the 2.7 to 3.6 V range, the maximum rate is 133 MHz. However, the latest Cube raises an error if you try to specify a master mode output rate in excess of 50 MHz. Is this just the Cube being out of date (50 MHz is the maximum rate for the STM32F7 series)?