Abstract: A method of cooling a complex electronic system includes preventing system air from passing through a front side and a rear side of a server system main board, organizing a plurality of electronic segments of the server system main board, providing cool air horizontally to the server system main board through a cool air intake provided at a position located underneath the front side and at a bottom side of the server system main board, using the cool air intake to provide the cool air to a plurality of cooling segments that redirect the cool air vertically at a 90° angle, and using a hot air exhaust after the hot air reaches the top side of the server system main board to redirect the hot air horizontally at a 90° angle and exhaust the hot air.