Always to run Linux we need SOC plus a minimum of two additional chipsets: RAM and FLASH.
That is why hardware which is able to handle embeddedLinux:
- consumes more energy than one chip solution.
- is more sensitive for power supply distortion.
- is less stable than one chip solution.
- generates more electromagnetic noises (extended memory bus, DRAM refreshing cycles).
- has a temperature of working range which is not so wide as one chip solutions.
- has a PCB which is much more complicated
- has longer BOOT-up procedure.
Of course embeddedLinux is nice because we can use almost all of the GNU software designed for PCs, and also we can develop software on a bare PC.
It means software development is much shorter and easier.
Anyway we have to always consider many aspects of the project and always select the best solution for the client.