Well that lets me out from buying the game. Takes 4 GB of Ram I have only 3GB ram. Maybe next time If I can upgrade my PC.
Yet mysteriously they say the game will work on XP, while the only version of XP that will recognize 4GB of RAM is the rare and seldom used 64-bit version.
It's possible that the 4 GB requirement is for Vista and later, while XP doesn't need as much. Consider the minimum specs just to run Windows itself with Vista and later are 1GB of memory, while the minumum for XP is only 64MB.
It might be worth trying a demo of the game on your computer -- especially if you have a good video card.