A gaming system includes a backplane and one or two additional PCBs that plug into the backplane. A first PCB includes a CPU and three PCIe edge connectors that plug into corresponding sockets on the backplane. One connector separates power and ground on either side of the connector's key. Another connector carries high-speed differential video signal pairs separated by ground to video ports on the backplane. The third connector carries CPU-related signals and at least one signal specific to a gaming machine housing the backplane. An optional second PCB plugs into the first PCB and backplane and provides gaming I/O functionality. The second PCB features a repurposed PCIe connector in which the first upper and last lower pin need to be activated to place the second PCB in operation. The first and second PCBs lack any connectors that receive external cables. Cable connections inside the gaming machine are made on the backplane.