I found this by Xyzxyz at
http://forums.civfanatics.com/showthread.php?t=411799&page=6
"I also needed reminding recently that your 8GB of RAM don't mean much. Civ IV BtS is still just a native 32-bit application, so the best it can do is make use of 4GB of your RAM, even if your comp has 8GB or more in it. The difference between running the mod on a 64-bit vs a 32-bit OS computer then is that bit (not meant literally) of memory that the OS itself takes up (which under a 64-bit system it can allocate to the 4GB (out of your 8GB) that 32-bit Civ IV BtS is NOT using). I suspect you're not helping yourself, btw, by running a lot of other application or subroutines 'behind' the game. I even disable my wireless internet and any other process that runs in the background before I start up a Civ IV BtS mod on a map larger than large. That way, you can play on Huge maps (low graphs settings, but highest 1920x1200 resolution - at least I managed to). Since the Earth map appears to be much larger than huge (from what I read), I think the MAFs should get you right around the Renaissance. Sobering. But inevitable. Try low graph settings, a very low resolution, and NOTHING else running on your comp, and you might make it to the end of the game w/ a 64-bit system and a lot of luck. I will try when I have some time."
So according to this low res and graphics actually helps prevent MAFs as well as using 64 bit Win7 (including shutting off system processes). I wonder if the speed of RAM and Chip help prevent MAFs...still browsing the internet.
Ah, found this by Markjohnson:
http://forums.civfanatics.com/showthread.php?t=224178&page=14
"This game will still get maf errors regardless of operating system because the game is 32-bit, so it still has memory limits.
To avoid maf errors set affinity to 1 processor only so it won't get interference from other tasks. Plus the game plays faster as well.
Make sure to run the processor editor, but it should already have the patch in 64-bit windows by default. but double check to be sure.
to set affinity:
1. Start game and minimize it (alt+tab out or maybe alt+enter)
2. start the task manager (right click the task bar and select," Start Task Manager", or press ctrl+alt+del and select, "Start Task Manager"
3.select Processes tab
4. right click CivilizationIV.exe (or whatever it's called) and select, "Set Affinity..."
5. uncheck all CPUs except 1 (doesn't matter which one)
This will reserve 1 cpu to the game only and nothing else. It should make it faster and lessen the maf error (but not eliminate it)"
Also, by bestbrian on the same page:
"Dude, you could have a Cray mainframe, the problem is with the software. Civ IV has a memory leak that was never fixed; you're going to have to periodically stop and restart. The bigger the map = more stuff to do = shorter time between reloads."
By Lemon Merchant at
http://forums.civfanatics.com/showthread.php?t=224178&page=13
"Just FYI, it isn't "outdated core components" in mods that cause the problem. Modder's can't change the game's graphics engine. That code was never released to the public, because it is proprietary. We can change the art files, and how the game works by Python, XML, and C++, but the underlying "core components" remain the same, and they were written in 2005, before machines commonly used more than 2 GB. The game was written for older technology, and the amount of memory used by the game is substantial. Add in the notorious memory leak, and you have a MAF just waiting to happen.
Running a very large mod with a huge map is known to cause issues. The computer has to hold a lot of things in memory, and paging out the graphics card RAM just adds to that. In most cases, it just causes things to slow down as more units must be paged in and out of memory, but eventually the user potentially hits a memory wall and the game crashes. Part of this is Windows itself, and part of it is a problem with the game and how it uses memory.
There are mods that are more prone to MAFs because of their size, but most "release" version mods have had the errors checked out and dealt with. That isn't to say that the mod doesn't always cause the problem by itself, because it can, but sloppy Python/XML/C++, is usually not the cause of a MAF. That causes other, more unfortunate errors, like C++ exceptions and loading faults. BAT 2.1 had a specific issue with late game saves, and it was due to a specific unit graphic in the art files being incorrectly defined in the XML. There was no coding involved, just something out of place. Those are the types of errors we can prevent (and we do try very hard), but MAFs are another animal all together."
Plus, by JosEph II at
http://forums.civfanatics.com/showthread.php?t=317648
"Right click My Computer then click on Properties.
Will bring up System Properties window, select Advanced tab.
1st section is Performance (you must be logged in as Administrator), click the Settings button.
1st tab is Visual Effects.
Default is, "Let Windows choose........my computer" ,
Instead select , "Adjust for best performance",
Or if you have some experience with Win XP , select "Custom".
After these changes select "Apply at bottom."
So hopefully Civ5 mods will be more stable.