The Macintosh Processor Upgrade (now discontinued), containing the PowerPC 601 chip, fits in the processor socket of the 68LC040 microprocessor. In order to install the board, the 68LC040 is removed from the computer's logic board, the upgrade board is placed in the 68LC040 socket, and the 68LC040 chip is placed in the upgrade board, retaining the computer's original microprocessor. This upgrade board is different from the Power Macintosh Upgrade Card (M2843LL/A), which only fits into the 68040 PDS in Macintosh Quadra 900, 950, 800, 700, 650, and 610 computers.
Because of space and power requirements, the Macintosh Processor Upgrade cannot be used in any Macintosh computer with an LC-style expansion card such as the Apple IIe Card or the LC Ethernet card.
The communications slot in the Macintosh LC/Performa 57X, the Macintosh LC/Performa 58X, and the Macintosh 630 family computers can be used when the upgrade is installed.
The Macintosh Processor Upgrade is compatible with:
* Macintosh 630 family
* Macintosh LC 475, 575, 580
*╩Macintosh Quadra 605
*╩Macintosh Performa 475, 476, 575, 576, 577, 578, 580, and 588
The following computers are in the Macintosh 630 family: Performa 630, Performa 635, Performa 636, Performa 637, Performa 638, LC 630, and Quadra 630.
The Macintosh Processor Upgrade requires System 7.5 (included with the upgrade).