Would it be theoretically possible to use a "desktop" CPU in a modified arduino?

Would it be theoretically possible to use a "desktop" CPU (Example: Intel i7-4770R) in a modified arduino board?

No.

Desktop CPUs typically have over 100 pins and external RAM. The ATmega328P has 28 pins and internal SRAM and FLASH.

If you 'modify' an Arduino board enough to support a desktop CPU you will end up with a desktop motherboard. :)

What did you intend to do with your i7duino?

ferapellido: Would it be theoretically possible to use a "desktop" CPU (Example: Intel i7-4770R) in a modified arduino board?

No

johnwasser: What did you intend to do with your i7duino?

Nothing, I was just curious

No, but you can get small form computers that are roughly the same size as Unos and Megas, if you wanted. Look for Rasberry Pi, PCdunio, Beaglebone Black, and others. These small form computers tend to use Arm chips (similar to the Due, but faster, and with more memory, but less support for interacting with physical hardware).

PicoITX motherboards are also pretty darn small, and are full PC compatible boards - though I don't know if GPIO or such are available on them...

I just looked at the specs for the pcDuino and it seems it blows RP away. Compare them at:

http://raspberrypihax.net/pcduino-competition-that-could-take-on-the-raspberry-pi/

The price points are about the same: $60