Zebadee is right about memory. On my Vista Ultimate 64 Bit PC, I was running 4GB of dual channel DDR memory, but it only recognizes 3GB. So I took out two sticks and put them one of my other PC's. I can not tell the difference with only 2GB RAM. It is just as fast. And two people I know with HP Home Premium Vista both run real slow and had me install another Hard Drive with XP Pro SP-2 for a dual boot option. Now they are fast and happy.