System fan speed is higher than cpu fan?

In bios diagnostics，cpu fan speed is 11xx rpm，system fan speed is 14xx rpm， their speed is controlled by bios automatically and we can not ajust manually.

Higher speed brings higher static pressure but lower airflow. A cpu fan is need more static pressure than airflow,because the wind need to through the heatsink's fin. System fan is need more airflow to exchange the air between chassis‘s inside and outside, their speed is need lower.

So , why the bios set the system fan speed is higher than system fan ? That's make nosense.

And , is there a simple way to check the fan speed on windows 10 ?