Intel OverDrive processors are a category of various Intel CPUs that were produced to upgrade computers.
ODP is the acronym for Over Drive Processor, however most OverDrives are ODPR (Over Drive Processor Replacement) chips:
To upgrade a computer to a new processor you just replace it with the new one. Their interfaces appear to the motherboard
like an older chip, so you don't need to worry about whether or not the motherboard
supports the higher speeds. ODP chips (like the DX2ODP66 or
the ODP486SX-25) in contrast were made for additional
sockets on the mainboard, the Performance Upgrade Socket.
On older versions Intel labeled the OverDrive chips with the external local bus speed they supported, like the
ODPR486DX-33. Since all these OverDrive chips
have the clock doubling feature, it was assumed by Intel that everyone knows that the CPU runs at twice the bus speed internally.