Instruction Speed of processor

I wish to drive a display that has 128 bits per row and 32 rows.

I wondering how long it takes to execute commands on the processor?

For example. How long it would take to turn a pin on ?

I have to shift out 128 bits in 450 microseconds, and be able to do that 32 times as quickly as necessary to reduce flicker.

Most instrctions execute in a single clock cycle, so 62.5ns at 16MHz, but library functions can slow down seemingly simple operations considerably.
But you can always go to port manipulation to claw back speed.

I wish to drive a display that has 128 bits per row and 32 rows.

So the duty cycle will be 1 in 32. That is the LED is on for only 1/32nd of the time. They are not going to be very bright are they?