That I know is complete crap. 64 bit programs in practice (at least ones from programmers that know what the heck they are doing) use the same amount of RAM to run. Sometimes even less. A 64 bit copy of IBT only needs 600MB to run, until you start testing, and then it uses however much you set it to. The 32 bit also needs 600MB to run. It can only test up to 4096MB though.
Check your programming language, and how you went about the problem. If you are not optimized, then it can likely need more RAM. If you do optimize it, chances are you can cut the RAM necessity by 50%.