What does a higher clock signal frequency actually mean for my AHRS?
What does the higher frequency of 16 MHz actually mean in this context?


The Arduino will run a bit faster (33% faster). Therefore it could calculate things faster. Whether you can poll the sensors more often might depend on the sensor. Limiting factors could be how fast you can communicate with the sensor, how often the sensor takes readings, what you are going to do with the readings, and whether it matters if calculations are a bit slower.

For a better response I suggest you post a link to the particular sensor, the AHRS algorithm you are using, and describe the application you are using it for.