Supreme Commander is kind of the successor of Total Annihilation, developed by Gas Powered Games and published by Square Enix on 20.2.2007. It is one of the first games to feature multi-core usage. However, that does not mean, the game distributes load equally on all cores but splits the main tasks such as sound, graphics and simulation into different tasks. So when having reached the maximum number of tasks, more CPU cores will not make a difference any longer and the single-thread performance of the CPU returns to being the important factor.
The game is known to cause problems with Nvidia drivers of version 460.79 or later. Game stutters and frames are dropping. There are three different approaches you can try, that might help you with that problem:
services.mscand stop & disable the NVDisplay.ContainerLocalSystem service.
Via the LAN you can connect with direct IP and enter the port. The game allows you to either choose the port randomly when opening a server, or to set it yourself. What doesn't work properly is players with the Steam version and DVD version in one game. The game can be started, but after some time the game is asynchronous (with constant messages that this is the case) so that the players sometimes see completely different states in the game.