Alternatively referred to as an ODP, which is short for OverDrive Processor, OverDrive is a microprocessor created by Intel. It was first developed for 80486s, and later included in the Pentium, Pentium with MMX, and Pentium II processor families. The OverDrive chip has a clock speed of 40 MHz or less and does not include a heat sink.
Most motherboards had an additional empty socket to accommodate this OverDrive processor. However, some had a replacement processor known as the ODPR, or OverDrive Processor Replacement, that would work as a replacement for the current processor in the computer. Today, OverDrive processors (shown in the image) are no longer being developed, supported or sold by Intel.
Note: The original OverDrive socket is now officially known as the Socket 1, and is a PDA socket with 169 pins.