Working from home at 25 MHz: you can do worse than the Quadra 700 (even in 2020)

The crop of personal computers available in the last decade of the 20th century was clearly faster, more efficient and more connected than their primitive ancestors. Clock speeds and transistor calculations were increasing rapidly, and the declining cost of memory and storage was opening up new avenues for personal computers to evolve from expensive desk accessories into multimedia and professional graphics design devices.

In 1991, the Intel i486DX was literally one of the hottest processors on the market. It was the first of which all needed a heatsink, and a cooling fan was a good option for processors with clich clockspeed. But for Apple Pal, the PowerPC architecture was still below the horizon, with only one choice left for high-performance Macintosh computers in the early 90’s: the Motorola 68040 microprocessor.

What an animal. The ‘040A’ was a significant upgrade over the 030 previously used by Apple Pal. It has 1.2 million transistors, four times more than its predecessor. This processor increased the size of the L1 cache by a factor of eight to 4096 bytes, and was the first 68k processor to have 68 non-board floating-point units (FPUs). Not without its drawbacks, when the ‘040 processor was a clear candidate for the next line of Apple’s premium workstations at the time. And this line will be known as “Quadra”, starting with the Quadra 700 and 900 models in late 1991.

While the floor-standing tower Quadra 900 was ranked number one in terms of overall performance and upgradability, its physical size and price tag were a barrier to entry for some. Its desktop-sized brother, known as the Quadra 700, was more impressive than both computers argued. After all, it was the Quadra 700 that was featured in Apple’s Paul Quadra television commercial and was clearly visible in certain Spielberg dinosaur-block action blockbusters.

Both computers were marketed to professionals looking for a home or office fee-based workstation-class computer, ideal for scientific, business and design applications.

Fast forward almost 30 years, and today the Quadra 700 is one of the most sought after vintage Mint Kintosh computers. Part of this may be due to Jeff Goldblum’s further supporting role, but there are other reasons as well.

The 700A is one of the few vintage Apple Pull computers to use a tantalum capacitor on a logic board instead of an electrolytic one. The latter capacitors inevitably leak electrolytic fluid, causing electrical instability and chordroding traces on the logic board. Tantalum capacitors are not electrolytic to leak and are not prone to failure.

Its peers include Quadra’s dedicated video RAM (VRAM), which is tightly connected to the processor, to improve other quality of life. Direct access to the frame buffer significantly improves video performance on the Quadra compared to other models like the IIC. Memory expansion capacity was also improved, with up to 700 supporting up to a total of 68MB of RAM. This amount was not possible in the projection, as it would still take several months for the CMM to develop to support this memory density. VRAM can be upgraded up to 2 MB.

I know all this because I’m a frustrated computer tinker who happened to be around a Quadra 700 in early 2020. In contrast to my way test of the IC for the Ars in 2018, the Quadra 700 actually introduced the technology to push the limits of desktop computing from the early 90s. Can these decades-old workhorse hold a candle to the 2020 multi-core behemoths? Thirty surprisingly capable; What about the Quadra 700 with its specs of the early 90s?

Project Quadra 2020 (or, how I spend my time during an epidemic)

700 I was sold in working condition, but otherwise “as is.” There are some things that may need immediate attention, not a floppy drive. Sticky, hairy, dirty – these were still common features for Apple Pal floppy drives with their doorless design. Over the years, all kinds of dust have been removed. Will have to wait another day for a full restoration of the tiny gear drive, however, in the meantime I had enough spare drives.

Half-assembled, I confirmed that the Quadra only runs fine. Apple Paul recommends not running the 700 for more than 200 minutes running the case, otherwise the idle cooled 68040 processor melts down. Not the best design, but it works nicely with a case shut.

Vintage Macs usually require a complete teardown and capacitor replacement before they can be safely operated. The above electrolytic fluid and underperforming capacitor can cause all kinds of electrical damage if thorough cleaning and capacitor replacement is not done. With tantalum capacitors on the logic board, the only real concern left was the power supply. Good dusting with compressed air removes most of the dust. The large capacitor inside the power supply will eventually need to be replaced, too.

At the moment, we had a modest amount of RAM and VRAM, a properly sized hard drive and a working system with three empty expansion slots. Until the restorations took place, everything went very smoothly. To deal with any leakage capacitor or failed lithium battery, the quadra was in top shape. This will be more than enough to play some rounds Speak up.

I think, however, we can do better.