A device configured to switch a clock speed for multiple links running at different clock speeds and a method for switching the clock signals are disclosed. A frequency divider derives a plurality of clock signals at different frequencies from a source clock signal. A clock switching controller selects a maximum data rate among data rates requested by a plurality of ports of links and outputs a transmit clock signal at the selected maximum data rate to the ports along with a clock enabling signal for each of the ports. Each of the clock enabling signals selectively enables the transmit clock signal for matching a data rate requested by each port. The clock speed may be selected and updated as required by the ports glitch-free in a known amount of time without interrupting data transfers on any of the other ports.