PC100 RAM & PM 7500/7600 w/Sonnet G4

Your 7500 & 7600 series don't take PC100 or PC133 Sdram. Powermac and clone with some 603 and 604 use 5 Volt Fast Page Mode (EDO)168 Pin. If you need more memory for this series, please go to otherworld computing. They are selling this memories 128MB 168 Pin Mac 5V DIMM 60NS 4K EDO for $20$$$.

The G3s and older Power Macs (like the 7500, 7600, 7300, etc.) use two different types of memory, which can't be interchanged. With the G3, the PC-100 (-66, and -133) memory is 3.3-volt SDRAM, whereas the 7500/7600's memory is 5-volt DRAM. You'd also need to apply excessive force, trying to install the PC-100 in the 7500/7600's memory slots.

David,

The downside is that the RAM is not interchangeable. This article:

http://www.macgurus.com/products/motherboards/mbppc75-7600.php

discusses 7500/7600 RAM and the voltage is not the same as PC100.

Unless the G4 daughtercard has its own RAM slots that take PC100 RAM, you'll need to find a different home for the orphan RAM.

The downside is it wont fit it's different RAM. If you place the chips side by side you will notice that the slot is in a different place to stop people inadvertently putting it in the wrong computer.
You can still pick up RAM for this computer but unless you are lucky enough to pick up a 128Mb chips on ebay (I brought mine for £15) they are prohibitively expensive.