When will it be added multithreading support?

[Chaingun]

It's no simple matter unfortunately. You have to program the game to use multiple threads from the start; it's very hard to try to add multithreading in late phases of development.

So, I doubt you'll be seeing significant multithreading in HoI3.

 

[Chaingun]

It's more complicated to program multithreaded applications = higher development costs.

Um, multithreading is in already, the game DOES ues multiple cores

Yes, but I presume this is to a limited extent? I don't know about the HoI3 internals. Either way, games are quite hard to parallelize.