A method of improving computer system performance during memory reads. Prior art computer systems experience a considerable time penalty during microprocessor reads from system memory. This time penalty is mitigated by the method of the present invention, wherein data is speculatively retrieved from system memory upon receipt of a microprocessor read request. A microprocessor initiates a read request which is decoded by a memory controller. Before the decoding has completed, the memory controller speculatively begins to retrieve data from the system memory device. Thus if the decode step determines that the requested data is in system memory, the time required to retrieve the data is decreased.