mike
I had "setup" the display at a lower rate and kept increasing the i2c baud rate till the display failed to update .
only one of my 6 displays could exceed 1mhz , one had issues above 400khz. I did not look at the pull up resistors .just trusted that the modules were fitted out appropriately. vcc was 3.3 v
the data sheet specs give a ic2 clock of 2.5uS 400khz so its probably not the best idea I have had.
i'm running them a 400k for reliability