So I just did a little project that had 65 Actors in the scene. 63 of them had scripts running. One, the player, had a rigidbody and would move around and interact with the other Actors that didn’t have a rigidbody but had colliders. I built my little demo and ran it. No memory leaks and FPS was constant at 60 the entire time. The machine I ran it on is a i5-10500 @2.50GHz with nvidia gtx 1650 with 4 GB vram. I ticked the option for building the game to run in the background so I could have Windows task manager open and running along side the game.
The memory usage dropped or increased depending on how many Actors were visible on the screen at once. it was just a little demo scene so ram usage went from 89 MB to 92 MB. The demo was setup so I couldn’t have more than 32 actors in the camera view at once. When I had the camera just look at the player and nothing else the ram usage dropped down to 89 MB. It wasn’t graphic intensive just used included materials for the objects.
Definitely not a very extensive test of the Flax engine.
Did something similar with Unity. The unity build of that demo started out using around 121 MB of Ram and would go up to about 144MB of ram but never went back down even when I was looking at just the player. The build from Unity capped at 40 FPS on my system.