The present invention is a method and apparatus enabling a low cost hardware upgrade path and low cost processor board retrofit for gaming machines. The enabling features include a two-board set made up of an industry standard form factor processor board (a single board system, able to support an operating system) coupled to an I/O adapter board, and further having a specially architected game kernel based on a UNIX-compatible operating system. The game kernel provides a consistent API to game applications, enabling quick and easy use of new hardware features while providing backward compatibility for existing game applications.