In Ashes of Creation (upcoming MMO), the founder Steven summoned
thousands of bears (NPCs) around players and the server didn't crash. AoC uses a modified Unreal Engine 5.
If they tried this in SC the FPS would be unplayable and the server would freeze.
From the comments:
"Problem of MMOs is the server having to handle all the clients and keeping them in sync to each other.
While a massive amount of NPC can of course also create some stress (though likely more for the client to render it, the server itself will just give you the position of them and what they do, not caring at all about the graphical elements), it's still just the server having to communicate this with a single client.
Meanwhile when you have just 20 players for example, all those player clients will communicate with the server and the server has to handle all this information not just for itself, but also to the other clients and this fast and of course constantly enough that everything runs in sync.
Depending on your combat system, this can get ugly very quickly.
In case of a game like WoW and alike, it's not of THAT much importance to do this 100 times per second, while on the other side a shooter for example has to be borderline perfect, when precision comes into play and even a 0,05s delay already ruins that - what of course causes a lot more stress."
All of which sounds strangely familiar from 'some other game' and 'some other forum'...... now, if I could just remember where...