Prior to being able to upgrade a machine by replacing the CPU, anyone needing a speed boost had to buy another system. Many individuals and companies replaced their systems about every two years.
Some people report that it takes a whole month to get everything hunky dory.
But with the CPU upgrade it is usually a simple case of plug and play. And of course now a lot of the new Macs don't even have SCSI, so if you've got a lot of money invested in expensive SCSI hardware that you can't afford to replace, you don't want to buy a new Mac. The answer is a CPU upgrade. It seemed like the Mission Impossible because the CPUs are soldered to the motherboard in those machines, therefore cannot just be replaced. But Newer Technology finally came up with a G3 CPU upgrade solution for those systems, announced in January of 1998 at MacWorld in San Francisco.