Motion of the cage in a high-speed angular contact ball bearing is experimentally investigated as a function of prescribed unbalance, up to operating speeds corresponding to three million DN. The predictions of cage motion made by the recently developed computer model, ADORE, are validated in the light of the experimental data. It is shown the cage whirl velocity is essentially equal to its angular velocity at all levels of unbalance and over a wide range of operating conditions. For the inner race guided turbine engine bearing, the cage/race interaction takes place directly opposite to the location of the unbalance and the severity of the interaction increases with the level of unbalance and the operating speed. ADORE predictions, over the entire range of unbalance and bearing operating conditions, are in very good agreement with the experimental observations.