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. The ODPR was capable of functioning as a replacement for the main CPU in the computer. Today, OverDrive processors (shown in the image) are no longer being developed, supported or sold by Intel.
The original OverDrive socket is now officially known as the Socket 1, and is a PDA socket with 169 pins.