I love the XP PRO operating system, Running on a quad core CPU with 2 GB's memory ( I THINK IT ONLY USES 2 CORES), it run's fine. However when I installed the Win 7 Pro 32bit, on a clean 1GB Samsung hard drive I have to say WOW. Beautiful. I thinking of updating the system to 4GB'S to get max benefit ( on a 32bit system, up to 4GB's max )It use's all the hardware to the full. I will keep the 64 bit in reserve for any future major upgrade. I will still be using my XP PRO for now and running both systems and in time will go over to WIN 7 PRO completely as it runs so very smooth in multitasking. Its so far the best operating system I have come across by Microsoft. I am running it right now and so far, very impressive. I just say one thing that the 2 DVD disc's 32 bit and 64 bit come with their own COA'S, which makes this a great buy.