All blocks used to create a patch can be run in either Control Rate or Audio Rate.
The rate that a block is set at defines the speed with which the given block transmits and/or receives data from the blocks it is connected to. When a block is set to run in Audio Rate, it will send and receive data at a rate of approximately 20 kHz (20,000 times per second).
Note that there are two different kinds of patch cords. Green cords represent data flows running at Control Rate while red cords represent sound or data flow running at Audio Rate.