However, I seriously doubt any game would have that kind of information worth over the 4gb.
Just to put something in perspective, I have windows 8.1 with the following up and running: Firefox, + Classic Shell, + Bitmeter (shows lan/net usage rates), + "7 Sidebar" with a clock, CPU Usage (also shows RAM usage, clock speed, and CPU temperatures), GPU Meter (shows GPU usage and GPU temperature), and Drives Meter, These alone use almost 3GB of RAM.
Steam adds another 200MB.
Bringing up GC2 TotA with an immense galaxy adds about another 700 MB.
So, if you only have 4GB of RAM, GC2 is already close to page faulting, which will start slowing down the game's performance, as we have discussed in other threads.
For comparison purposes, Windows 7 uses a bit less memory. I just checked my wife's PC, on which she has the sidebar with a clock, CPU Usage, GPU Usage, and Network Monitor, and Live Mail up and running using a bit more than 2.3GB RAM. FireFox adds about 300 MB to that.
I think we can see from this that the 4GB RAM minimum figure being talked about on these forums is an absolute bare minimum to run anything on a modern PC.
Trying to calculate how much GC3 is going to need just for ships is also very short sighted. Ship designs need very little memory compared to how much memory is needed just for a segment of the galaxy, with all of the stuff that must be put in each tile, such as stars, planets, ships, resources, anomalies, path lines for trade routes and asteroid mine delivery routes, tile borders, etc. etc. And that isn't all that GC3 is going to have in its address space. Oh, and don't forget all the executable code.
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EDIT---> I just found out that the game I am playing is a gigantic galaxy, not an immense one. I also tried loading a Tiny galaxy, just to see how much RAM would be allocated to it. It was about 150MB smaller than for a gigantic galaxy. Since the Tiny was a new game without any turns, and the Gigantic was after exploring the entire galaxy, seeing two major races die due to wars with other races, and having conquered half of the drengin's planets (about half a dozen planets), it is quite likely that any comparison between the memory usage is skewed a bit.