However, System Profiler doesn't confirm any change in speed in either machine - the 300 still shows as being a 300 (in OS 9 and OS X) and the 350 is still a 350 !!
The processors are securely seated and locked down with no missing pins.
Can anyone tell me what I might have done wrong and/or why the profilers show no (apparent) change in speed?
Many thanks and ...
Regards to all
DL
Yes, that is correct.
If you swap processors, you have not swapped processor
clocks. The clocks are still running at the old speed.
With newer Macs, the clock is on the processor card. When you swap processor cards, you swap clocks too.
With the B&W G3, the clock is not on the processor. The clock is in a different place on the logic board. The clock in the 300 MHz system is still ticking at 300 MHz. It does not know that you have put a processor capable of running at 350 MHz in the processor socket.
You can think of the speed rating on a processor like the speed rating on a car tire. If a tire is speed rated for 120 miles per hour, it means that the tire can safely go at 120 miles per hour. If you put it on a car that is not capable of going that fast, though, the tire won't make the car go that fast!
On your B&W G3, the processor clock is controlled by a series of jumpers inside of a "jumper block" on the logic board. You must swap processors and
also swap jumper blocks.
The jumper block is a long, very narrow bit of plastic just to the right and slightly below the processor when you have the computer open with the front facing toward you. On some B&W G3 systems, there is a loop of tape around it saying that the warranty will be void if the loop is removed. On other B&W G3s, the jumper block is actually taped down to the logic board with a seal that tells you the warranty is void if the seal is broken.
This picture shows you where the jumper block is. The arrow marked "A" points to the jumper block.