Yep, common error, if you have a 64 bit os and 4+ gigs of ram you should use the fix that a player made.  I think you can find it on the mod forum.

I had my 1st ever "out of memory error" a couple days ago.  XP sp3, 32 bit, 3gb ram.  So its not just 64-bit OS.

Normally in late-game the game slows down, has constant disc access (sign that it is out of "real" memory and pounding on the virtual memory), and crashes every 20-30 turns.  I interpret all that as signs that it is ALMOST out of memory, but its only "officially" been out the one time.

It can only push so far before the the system / run time say "No, you cannot have any more memory!" and then it crashes. The cause is that some stuff that is not being used and will never be used again is not being recycled, resulting in the game eventually running out. (On 64 bit systems, each application can run in its own 64 bit address space, meaning each application theorectically could use more memory than most people's hard drives have space for files)

This is more technical stuff that you likely wanted to know, but it is late and I have been working on memory related stuff for a custom operating system kernel I am (slowly) creating.

Now for something useful: I seem to recall a setting in Windows XP for how much of the hard drive it could use to fake having more memory that it really did; however I do not recall seeing it in Vista.

No doubt it is complicated! I guess i am thinking in terms of what other games can do.... i mean you can run most games on crappy systems with below minimum requirements of memory and all that ever happens usually is that it runs very slow, the memory never actually 'runs out' even though we know there is not physically enough memory in place. Elemental on the other hand manages to declare the memory ran out even on above minimum requirement systems!!

Elemental may not be recycling memory properly but if that was the case, i would expect the framerate to gradually decrease, but that never happens. Most of the time the game is running at peak performance then suddenly declares 'out of memory'. Occasionally there may be a sudden and dramatic drop in framerate at which point i will realise the game is finished because at that point if i try and save, it will certainly go 'out of memory' and crash..... catch 22, once i notice the problem, it is too late to do anything about it.

Wait... i remember what i used to do in Galciv now... i used to run another application before starting the game, then when i see that big framerate drop, i will close the other application and save the game - worked like a charm! (but won't work so good for elemental due to often not seeing any performance drop before out of memory error pops up)

You're only going to suffer notable performance degradation before going OOM if you have little enough system memory that the game digs in to the swap file significantly. As a 32 bit app though, Elemental can't use more than 2GB no matter how much you have.

You can't reduce the framerate and expect memory utilization to go down, it doesn't work like that. One of the issues we're dealing with is that certain internal functions in ATI's x64 drivers don't recover used memory... ever.

As others have pointed out, if you're on a 64 bit OS and have OOM issues frequently (not everyone does), you can give the large address header patch a try but we can't support that ourselves. It might cause some DirectX issues but should improve your memory longevity considerably.