Hi Trainee123,
This specification refers to the maxim speed at what you can actually read or write to a digital line of the module. That means that It would take you at least 100 ns to turn a digital output of the module ON or to turn it OFF.
Your program, the hardware you use ( FPGA, cDAQ, etc..), OS, etc... affect the final execution time but you should consider the hardware/module limitations as well before deciding what module is appropriate for your application.
Erwin Franz
Certified LabVIEW Architect, Certified TestStand Developer