SuperMac C500 and C600 CPU Upgrades

The SuperMac C500 and C600 are unique among Macintosh clones. They were the first clones to use a ZIF socket for easy processor replacement. Umax made processors in speeds from 140 to 280 MHz, as well as the CacheDoubler, which provides a double-speed (80 MHz) level 2 cache four times as large as the 256 KB motherboard cache.

Umax SuperMac C500Both the C500 and C600 are designed around a motherboard with a 40 MHz system bus, limiting maximum CPU speed compared with machines such as the J700 and S900 that used Apple’s daughter card socket with a 50 MHz system bus, which is the very thing CacheDoubler is designed to address.

Manufacturer/Model CPU Speed Cache Size Cache Speed
Phase 5
Aptus G3/260 260 MHz 512 KB 130 MHz
Aptus G3/300 300 MHz 1 MB 150 MHz
Aptus G4/350 350 MHz 1 MB 175 MHz
603e/240 240 MHz 256 KB 40 MHz
603e/240 with CacheDoubler 240 MHz 1 MB 80 MHz
603e/280 with CacheDoubler 280 MHz 1 MB 80 MHz

Also see our Guide to G3 Accelerators for Level 2 Cache Slot for other upgrade options for the C500 and C600.

Keywords: #supermac #cachedoubler