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.
Both 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 |
| Umax | |||
| 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
