PGA970: PGA970 SPI clock

Hi 

We are experimenting a software routine reading demod1_data and demod2_data registers. Erronously we set pga970 SPI clock to 1,25Mhz and acquisition systems works fine. We would like to know if the spi clock requirement reported in datasheet is correct (maximum SPI rate is 1Mhz). In the contrary case could you provide maximum or suggested SPI rate.

thanks in advance 

Carmine