Maix-M1 Flash Clock Rate (SPI3)

I’m trying to optimize my M1 design by speeding up flash writes. SPI3 is used for the flash interface. The W25N01 flash part used in in the Maix module is rated up to 104M and the K210 specs indicate that SPI3 can run at up to 100MHz. Even if this is too high something significantly better than the 25M rate coded in the standalone demos would be expected. I’ve been able to slightly increase the rate to 27.5M but higher than that doesn’t seem to work.

Can anyone provide some suggestions on what might be wrong?

Thanks!

In my MicroPython for K210 implementation SPI3 works without issues at 80 MHz.
w25qxx_init, machine.flash_speed