Apple Performa 6200CD

Much like my Performa 600, the Performa 6200 is another example of questionable Apple tactics when it comes to machine design. Whether motivated by speed of entry to the market, or simply bound by dollar figures, the 6200 is a crippled machine ahead of it's time.

The Performa 6200 (The CD denotes it came with an inbuilt CD-ROM drive) was one of the first Apples to come out with the new 75mHz Motorola 603 PowerPC processor. Unfortunately Apple, under CEO Michael Spindler, decided to merge new technology with old - placing the PPC603 on effectively a Quadra 630 mainboard. This Apple was one of a series (5200, 5260, 6200, 6300 & 6320) with fairly serious hardware issues and compatibility problems.

So what does this mean? You have a 75mHz 64-bit PPC603 running on a 37.5mHz bus, using a 32-bit memory path and bizarre devices setup. On the earlier PPC601 machines, Apple installed 32-bit 72 pin memory in pairs, which "merged" to fit 64-bit. With the 6200, data/instructions read from memory take four cycles instead of two, with proper 64-bit memory access (Read 32bit, store high, read 32bit, store low).
And then there's the serial hardware that clearly somebody got bilked on, as it doesn't do hardware handshaking - meaning you can't use an external modem faster than 9600bps. As such, most of these Apples shipped with the serial port plugged and a 14.4k modem in it's Communication slot.
The 6200 was also one of the first Apples have an internal IDE hard drive, on an 8-bit controller, instead of SCSI like always, although it was SCSI capable. Apparently to increase network stability, it is recommended to plug a terminator onto the empty DB-25 SCSI port.

And then there's the multiple buses.
The 6200's 64 bit processor bus is divided into two 32 bit busses, with various devices hanging off them, at differing speeds. On the high 32, Ethernet, SCSI, audio and ADB at 10mHz. On the low 32, memory and graphics at 33mHz, and IDE at 12mHz.
The motherboard has a single clock, at 25mHz, the bus speeds are all ramped up/down through multipliers of this clock signal.

What does this mean? Surfing the internet sucks on the thing (Ethernet/Serial must pass through the CPU to get to the memory, display and disk access), resulting in slow speeds, typed characters disappearing while a page is loading. Graphics will appear to stop, or slow down dramatically with lots of disk access. Printing while spooling and resizing takes days.