Texas Instruments 486DX4 Microprocessor

Despite the name, the Texas Instruments 486DX4 microprocessor does not run internally at four times the memory bus speed, but rather at triple the external clock speed. Since Intel reserved the DX3 designation for a 2.5 times clock multiplier that never reached the marketplace, they created the newer moniker, the DX4, which other licensees such as IBM, AMD, SGS, and Cyrix also adopted. Although Intel never produced one, clone makers such as Advanced Micro Devices (AMD) and Cyrix sold 5x86 processors that were actual clock quadruplers.