Abstract: An apparatus comprises processing circuitry to perform data processing in response to instructions; prediction state storage circuitry to store prediction state information; prediction state training circuitry to train the prediction state information in response to events detected during processing of instructions by the processing circuitry; and prediction circuitry to predict, based on the prediction state information, a given speculative action to be performed in response to a given prediction trigger event; in which: the prediction circuitry varies, based on one or more current system resource conditions of the apparatus, at least one action selection criterion used to select which speculative action is to be performed.