This question already has an answer here:
I want to release come kind of computation engine as an open source project. For the whole source and usage, I am fine with the content of the GPL but what I want to make sure:
There should be a restriction for: Each computation is allowed on a maximum of 4 cpu’s / threads / parallel processes at the time.
Important: Nobody except us may have the right to extend or remove or revoke this restriction without our explicit agreement and confirmation.
It is possible to use a multi license for that project, so that anybody can get in touch with us to ask for a higher license to change the restriction.
I am aware of that this kind of restriction is just limited in a legally respect and not technically.
Just to make sure, if someone would like to run a paid service or whatever under the restriction just use 1 CPU - they are allowed - this is not something I am interested to prevent. I just want be safe when someone is doing a real business out from this.
I asked via mail at FSF to check wether it is possible to handle this restriction via Chapter 7 of the (A)GPL. The answer was given by a volunteer: Section 7 lists all of the A/GPL-compatible further terms. The restriction you propose would be incompatible, and would have the effect of making the software nonfree and proprietary.