Powermac g5 2.0/2.3 dualcore cpu installation into quadcore m/board

Hello everyone.

I want to install two 2.3GHZ or 2.0GHZ (970MP) dualcore processors in to powermac g5 quadcore motherboard. I think that the quad system use two similar 970 MP'S chip which have 2.5 GHZ freguency. The dualcore logicboard seems similar as quadcore board but has only one cpu slot. These cpu (2.0/2.3/2.5 dualcore) have similar architecture -PPC970MP and cpu-to-borad connector. I will use for this installation 1000W power supply from powermac quad core system.

And i think that the 2.0/2.3GHZ can be installed in to quadcore logic board.

Why i want to do it? 2.5 GHZ Dualcore cpu too HOT and too expensive and it is difficult to find to buy it. So 2.0/2.3 cheaper then 2.5GHZ, easy to find and more stable, colder. Will quadcore board work with 2.0/2.3 GHZ dualcore cpu's? What you think? Maybe somebody already did it?