CPU Upgrade to future intel processors

Here is a guide on how to remove the CPU

iMac Intel 21.5" EMC 2308 CPU Replacement

As far as upgrading the CPU you the i7 is not possible because the current CPU and the i7 have different sockets. You could try upgrading to a CPU with the same socket as the Core 2 duo currently in the iMac here are the specs for the core 2 Duo.

http://ark.intel.com/Product.aspx?id=414...

To be on the safe side I would probably get a CPU with the same Max TDP (wattage) and voltage range as the Core 2 Duo.

The best LGA775 socket, 65W TDP, 0.8500V-1.3625V voltage range CPU out there is this one:

Core 2 Quad Q9550S (Yorkfield), spec# SLGAE (E0) Here is a list of the CPU's:

http://en.wikipedia.org/wiki/List_of_Int...

This s not an i7 but it will definitely outperform the Core 2 Duo. You will probably have to reinstall Mac OS-X AND OR come up with a driver somehow to accept this CPU since Apple never made a Mac with this CPU.