The RackMac TS 750/300 by Marathon Computer is a powerful rack-mounted Macintosh clone featuring a 300 MHz PowerPC 750 (G3) processor, up to 272 MB of RAM, and SCSI-II storage. Designed for professional use, it fits within a 4U 19-inch rackmount enclosure, making it ideal for technical studios, server rooms, or institutional labs.
The machine supports dual processor upgrades, includes 6 PCI slots, and runs classic Mac OS versions 7.5.3 to 9.0, though support beyond 8.1 was unofficial. It came in configurations ranging from 32 MB to 272 MB of RAM, and shipped with a 4 MB IX-Micro Twin Turbo graphics card.
RackMac TS 750/300 – Full Technical Specifications
| Specification | Details |
|---|---|
| Model | Marathon RackMac TS 750/300 |
| Processor | PowerPC 750 (G3), 300 MHz |
| Backside Bus | 150 or 300 MHz (varied by config) |
| System Bus Speed | 50 MHz |
| Processor Upgrade | Daughtercard (Dual processor ready) |
| Architecture | Tsunami |
| Level 1 Cache | 64 KB |
| Level 2 Cache | 1 MB (backside) |
| Data Path | 64-bit |
| RAM Type | 70 ns 168-pin DIMM |
| Standard RAM | 32, 144, or 272 MB (custom configs) |
| Maximum RAM | 1040 MB |
| RAM Slots | 8 |
| Motherboard RAM | 16 MB |
| Graphics Card | IX-Micro Twin Turbo, 4 MB VRAM |
| Max Video RAM | 8 MB |
| Hard Drive | 2.1 GB SCSI-II |
| CD-ROM | 8X |
| Floppy Drive | 1.44 MB (manual eject) |
| Expansion Slots | 6 PCI |
| Expansion Bays | 1 (5.25″ external), 2 (3.5″ internal) |
| Ethernet | AAUI, 10Base-T |
| Modem | Not included |
| Battery | 3.6V Lithium |
| Case Type | Rack-Mountable, lockable front panel |
| Form Factor | Marathon Rack (4U, 19″) |
| Supported Mac OS | 7.5.3–7.6.1, 8.0–9.0 (Officially up to 8.1) |
| Dimensions (HxWxD) | 7.0 x 17.25 x 17.75 inches |
| Weight | 42 lbs |
| Release Date | May 1, 1998 |
| Discontinued | December 31, 1998 |
| Original Price | $5100 – $6200 USD |
Built for the Rack, Engineered for Professionals
The RackMac TS 750/300 was built for users who needed Mac OS compatibility in a secure, rack-mountable enclosure. With support for dual processors, expandable RAM, and multiple drive bays, it was well-suited to professional media production, server deployments, and technical labs.
This model was part of a niche market of Mac clones that leveraged Apple’s temporarily open licensing era, delivering performance and flexibility in non-standard form factors.
