The Hardware Research 750/275 was one of the most advanced rackmount Mac clones ever produced under Apple’s short-lived licensing program. Introduced in early 1998, it featured a 275 MHz PowerPC 750 (G3) processor, a high-speed 1 MB backside cache, and dual-processor upgrade capability. This model was targeted at professional environments requiring robust and scalable Mac OS computing in rackmount form.
The system was built on Apple’s Tsunami architecture, the same board design used in Power Macintosh 9500 models, but enhanced with modern G3 power. It shipped with either 128 MB or 144 MB of RAM, a 6.0 GB SCSI hard drive, and an 8 MB ATI XCLAIM 3D video card—making it ideal for rendering, video editing, or scientific applications. With a $6,850 USD price tag, it was one of the highest-tier configurations offered by Hardware Research.
Official support included Mac OS 7.5.5 to 8.1, although the machine was capable of running Mac OS 9.0 unofficially. Let’s dive into the detailed specifications of this rare, high-performance G3 rackmount Mac.
Hardware Research 750/275 – Technical Specifications
| Specification | Details |
|---|---|
| Introduction Date | January 1, 1998 |
| Discontinued Date | December 31, 1998 |
| Processor Type | PowerPC 750 (G3) |
| Processor Speed | 275 MHz |
| FPU (Integrated) | PowerPC 750 (G3) |
| System Bus Speed | 45.83 MHz |
| Backside Bus Speed | 275 MHz |
| ROM Size | 4 MB |
| Data Path | 64-bit |
| Level 1 Cache | 64 KB |
| Level 2 Cache | 1 MB (backside) |
| RAM Type | 70 ns 168-pin DIMM |
| Standard RAM | 128 MB or 144 MB |
| Maximum RAM | 1040 MB |
| RAM Slots | 8 (supports interleaving for faster performance) |
| Standard VRAM | 8 MB (ATI XCLAIM 3D) |
| Maximum VRAM | 8 MB |
| Hard Drive | 6.0 GB SCSI |
| Standard CD-ROM | 12X or 24X |
| Floppy Drive | 1.44 MB (manual eject) |
| Modem | Not included |
| Ethernet | AAUI, 10Base-T |
| Case Type | Rack-Mountable |
| Form Factor | 19″ Rackmount |
| Expansion Slots | 6 PCI |
| Expansion Bays (Free) | 1 external 5.25″ bay |
| Battery Type | 3.6V Lithium |
| Built-in Display | None |
| Supported Mac OS | System 7.5.5 to 9.0 (Apple support up to 8.1) |
| Dimensions | 10 x 17.25 x 17.75 inches (H x W x D) |
| Average Weight | 52 lbs (23.6 kg) |
| Original Price | $6,850 USD |
| Estimated Current Value | N/A – Rare collector’s item |
| Architecture | Tsunami (Power Macintosh 9500-based) |
Why the Hardware Research 750/275 Was a Powerhouse
The Hardware Research 750/275 represented the pinnacle of G3 performance in a Mac OS-compatible rackmount system. Its combination of 275 MHz G3 speed, large L2 cache, dual CPU upgrade potential, and ample RAM/VRAM made it a premium option for professionals with demanding workflows. Whether deployed in a multimedia rack, data cluster, or custom computing rig, it stood far above consumer-level systems of the same era.
As one of the last G3-based clones before Apple ended all third-party licensing, the 750/275 is now a historical benchmark—marking the limit of how far third-party Mac-compatible innovation could go before being shut down.
