Why don't you try it and let us know...
In general, here's what a large program does when it doesn't have enough RAM:
1. it will refuse to start
2. it will crash when it runs out of memory (the better ones will actually try to save first, but they won't always succeed)
3. it will use virtual memory, i.e. it will be slow, it will stutter, and it will make your hard drive fail eventually