I know I’m posting in the incorrect thread, but I couldn’t find more suitable forum than this one.
1: I’ve heard from couple posts that Unity3D is limited to single graphic card, single core and 4GB of RAM regardless CPU architecture, SLI combination and amount of physical cores in CPU. Is that true?
2: Does Unity3D have any limitations at all? Can I create absolutely astonishing game that would require like 880M, 16GB RAM and 3.5GHz quadra-core? I know I should try to make it as small as possible, but you know. Can I do everything in Unity?
I believe the 4gb limitation is a limitation of 32bit applications, so yes unity 4 is limited to that amount of memory, the other limitations are specific to certain parts, the engine itself cannot be cross threaded, but your own code can. But based on your question you asked if you could make a game more complicated than Crysis 3, well if you have a team that big, given time yes with Unity 5 you can build to 64bit. But as 1 person… To build Crysys would be pretty much impossible in 1 persons lifetime.
If anything is going to be a limiting factor, it’s going to be your own ability and time. The engine you choose is going to be much further down the list.
Single graphics card: Don’t know but I don’t think so - the SLI stuff is supposed to be taken care of by the driver, I believe?
Single core: No. Unity multithreads a number of core systems.
4GB RAM: No. You can only use 3GB in the editor (if you’re on a 64-bit system - only 2GB if you’re on 32-bit) but you can make 64-bit builds which support much higher amounts of RAM. In Unity 5, the restriction on the editor will go away as a 64-bit version of the editor will be shipping.
You could certainly create something that required an 880M with 16GB of RAM and a 3.5GHz quadcore CPU; the simplest way would be to make incredibly inefficient artwork.