"I'd add more RAM. It depends on your tree but my 12GB (3-4GB useable by FTM) is not enough. Program crashes each day due to out of memory issues."
On XP the most Windows can use is 3 Gb approx (RAM plus Swapfile/Pagefile). To the best of my knowledge the most any 32 bit program can use on 64 bit OSs is also 3GBytes.
What error message do you get when FTM2012 "crashes"? Does it say "3 GBytes not enough" or something like that?
I know that on XP I get error messages to show null pointer assignments, probably caused by the .Net framework but I've never seen the whole of the memory taken up by FTM2012.