Upgrading an iMac 7,1 CPU

[olm]

Hello,
I have an old iMac 20'' 7,1 from 2007 with an Intel Core 2 Duo T7300 2.0GHz CPU (Socket PBGA479 or PPGA478, 800 MHz FSB).

Is it possible to upgrade it to an CPU with higher FSB speed like the Intel Core 2 Duo P8400 with 1066 MHz FSB?

 

[BadAsAl]

...

 

[BadAsAl]

I originally thought the CPU was soldered on but that might not be true for that model: http://lowendmac.com/2016/cpu-upgrade-options-for-mid-2007-imacs/
With all computers but with Apple especially I always look to see if the manufacturer had a model with the processor I want to go to. If they do I feel safe upgrading. If not, there is no guarantee the processor will work even if it physically fits in there.
What I would be looking at is potential gain for cost.
So your current CPU rates 1196 on passmark.com
The best processor that Apple put in a 2007 iMac is a X7900 which gets 1679 on passmark.com
The P8400 *might* work but only gets you to 1464 which is not much of a bump.
If you are looking to boost performance, just put an SSD in there.

 

[olm]

Thanks. I want to upgrade the CPU because the latest Mac OS version (Sierra (10.12)) isn't compatible with Merom-based CPUs, so I need a Penryn-based CPU like the P8400. When the CPU has a higher FSB frequency it just means that some cycles are wasted, but it should be compatible with the iMac's 800 MHz FSB mainboard. Do you agree?

 

[BadAsAl]

I assume Mac's are the same as the PC in that the motherboard/logic board has to be told to support the CPU. It is done with the BIOS on a PC, not sure how on a Mac. I have never tried to swap a CPU on a Mac of any kind before so I have no experience there.
It may work, it may not. It's a bit or work to get in there and try but if you like that kind of thing it can be fun.