A multi-core processor system supporting simultaneous thread sharing across execution resources of multiple processor cores is provided. The multi-core processor system includes a first processor core with a first instruction queue and dispatch logic in communication with a first execution resource of the first processor core. The multi-core processor system also includes a second processor core with a second instruction queue and dispatch logic in communication with a second execution resource of the second processor core. A high-speed execution resource bus couples the first and second processor cores. The first instruction queue and dispatch logic is configured to issue a first instruction of a thread to the first execution resource and issue a second instruction of the thread over the high-speed execution resource bus to the second execution resource for simultaneous execution of the first and second instruction of the thread on the first and second processor cores.