It's logical that I could upgrade to any one of CPUs that Apple shipped this computer with. What I was wondering on the outside chance, was if a completely different CPU that Apple never used could work?

For example, I have an eMachines computer. This particular computer comes in one of 5 configurations from eMachines, not one of which is a quad core. My particular model was a single core. If one determines the chipset/socket and also the motherboard type, you can break the rules and use other CPUs. It is never the case that only the CPUs used by the manufacturer will work. In my case, I added a quad core AMD Phenom - despite everybody saying it would not work - and it works beautifully.

Apple does not use proprietary guts in their computers. This chipset, socket and motherboard are all made by third parties and may be compatible with other CPUs.

Everywhere else I ask this question, people give me the same institutionalized answer regarding the CPUs that came with this build. I was hoping to go deeper here. Thank you.

Model Name: iMac
Model Identifier: iMac7,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.4 GHz
Number of Processors: 1
Total Number of Cores: 2
L2 Cache: 4 MB
Memory: 2 GB
Bus Speed: 800 MHz
Boot ROM Version: IM71.007A.B03
SMC Version (system): 1.21f4
Serial Number (system): 737515A9X89
Hardware UUID: 00000000-0000-1000-8000-001B639AE04C