Hi Stephen:
For loading the orthomosaic you want to make sure that you have enough RAM. For editing, the GPU is next on the list that would be heavily used.
You can read more about what components are used for what steps HERE.
In the links below you can find relevant hardware related information:
Processing Speed
System Requirements
Pix4D Computer hardware community benchmark
PC Hardware Articles in Category “Pix4D”
Cheers,
Ina