OverClocking
It has been said that the IIsi was based on the IIci, therefore it shares many of the same components as the IIci. Also it is said that the IIsi was designed to run at 25Mhz therefore the IIsi should have no problems overclocking. If the goal is to get more speed you should get a Quadra. I would not overclock over 25Mhz. It is worth it for the 50% video speed increase.
A component called an oscillator regulates
the clock speed the processor will run at, with 68k macs the oscillator
will run at twice the processor speed therefore a 40Mhz oscillator will
run the computer at 20Mhz. To upgrade the computer to 25Mhz you add a 50Mhz
oscillator.
Material List for Overclocking :
Soldering Iron Preferably <30WStep By Step Guide :
Small Pliers
14-pin DIP IC socket highly recommend but optional
Oscillator