The problem: Frequent memory errors in RoM 2.5 with or without MegaCivPack (this also applies to other mods, this is not a problem of RoM only) Background: 32bit Windows (32bit XP and 32bit Vista) lets programs use only 2GB total of memory (either physical or physical+virtual combined). The main problem is that Vanilla Civ4 BtS already goes near this limit and with many mods Civ4 uses more than 2GB which results in Memory Allocation Errors. But there is a way to circumvent this (Although there is still the chance that this won't work for your PC, there are just to many possible configurations) XP and Vista do allow the total of memory used by programs to increase to 3GB which is enough for RoM. Warning: Read and understand the next paragraph completely before changing anything. I can not be held responsible for any damage to your computer or OS. For XP Home and Professional Follow these Instructions http://www.finitesolutions.com/Support/Enabling3GB/tabid/70/Default.aspx to enable 3GB Support for your Windows. There are a few addons to this. 1. Steps 1 and 2 in the mentioned guide are optional, you should Back up your data regularly and knowing something about the recovery console can come in handy too. 2. Instead of just adding /3GB to the first entry I prefer making a copy of the multi(0)..... part so you can load windows with the default 2GB option if you have programs that don't work properly. NOTE: ALWAYS copy something from your OWN boot.ini because there may be settings unique to your Windows. NEVER copy from the guide above or below. This should look like this multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Home Edition 3GB" /3GB /fastdetect /NoExecute=OptIn multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Home Edition" /fastdetect /NoExecute=OptIn This way you get a Boot Menu where you can boot into plain 2GB Windows if something goes wrong. 3. After the reboot you may encounter wrong resolutions or refresh rates. Even if you don't notice anything unusual, please check the following: Go to Control Panel - open System - click on Hardware Tab - click on Device Manager. Open up Display Adapters. If you see any yellow exclamation mark in front of your Graphics Adapter your drivers aren't loaded properly. The solution to this problem is adding another option to the Boot.ini Open up Boot.ini as described in the above guide. Add " /userva=2900" without quotation marks to your /3GB boot option. Then restart your PC. Do check your Display Adapter again. If it's still not working change 2900 to 2800. Decrease this as long as your display drivers aren't working properly (although settings lower than 2300 or 2200 might not really work for solving the original problem). It should look like this now: multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Home Edition 3GB" /3GB /fastdetect /NoExecute=OptIn /Userva=2900 For VISTA: (blatantly copied from this thread http://forums.civfanatics.com/showthread.php?t=224178) - Now we need to make Windows Vista (32-Bit) ready to support more than 2 GByte. - Open a command prompt with Administration rights. You find it under "Programs->Accessories->Command prompt" click right and select "run as administrator". - Enter "bcdedit /set IncreaseUserVA 3072" (without quotes) in the command window and press enter. After that restart windows Conclusion: I'm using this for about a month now and I haven't had any MAFs since then. Not even with RoM 2.5 Megacivpack. Turn times in late games are still long but that's more because of my rather old PC. But since every PC is different there is no guarantee this will work on your system. System Specs of mine: Athlon XP 3000+ 1,5 GB RAM GF 7600GT Any questions/comments are welcome.