A method for testing synchronization between a first graphics processing
unit coupled to a second graphics processing unit. The method includes
detecting whether an incoming synchronization signal has been received,
determining whether the incoming synchronization signal is received from
one of the first graphics processing unit, the second graphics processing
unit and an external synchronization signal, and indicating on a control
panel one of a first and second synchronization input/output ports on one
of the first graphics processing unit and the second graphics processing
unit as an input port and the other one of the first and second
synchronization input/output ports as an output port, if the incoming
synchronization signal is received from the one of the first graphics
processing unit and the second graphics processing unit.