paliometoxo, its about memory management, system resources + the programs i use are made for 64 bit... XP 64 bit i think its the best OS for professional use these days all tho i have Windows 7 on my 19" VIAO Laptop and its incredible. I've spend about 2 hours with Vista in my life and it proved once again that you must always hop over 1 version... so, my next windows will be Windows 9