Is internal networking performant enough for me? (MMORPG, instanced(no big world))

I have an idea to use dedicated unreal server with multiple instances ran on each physical/cloud/VPS machine. How that idea is resource/cost wise? How much unreal servers(serving 3 to 10 people) can physical server handle? What are pitfalls? How resource greedy is it?

We don’t have your game, so can’t really tell you. Remember it has to load your assets and such before you know the memory footprint. So you’d better just make a mockup version of your game and check for yourself.

i tried one instance, but wont find people for testing it on huge load, memory and cpu were just ok, i think there would be some problems with networking that’s not easy to benchmark

Rozenbor, have a look at this mmo starter kit, he has already tested it with 140 players in a dedicated server. https://forums.unrealengine.com/showthread.php?53208-MMO-Starter-Kit