Farside is correct. Was a time windowz could not see past 128 megs of ram, now that limit is 2 gigs, so having 4 gigs is absolutely useless unless you just want to be able to say you have it. From what I've heard, speed and ram are the most signifigant factors, as well as a very big and fast hard drive. These are all important for a pc to have although I also understand that because poser is very energy consuming on any pc, it is not a good idea to have a celeron or anything but a pure intel chipset. I know several folks that had their computers literally burn up with rendering because the computer could not take the stress involved to render poser day in and day out with these newer meshes and textures. A graphics card is totally useless for poser at this time, you can add this later if ever need it. XP Pro is absolutely not necesarry at all and just an extra cost because xp pro and xp home run graphics exactly the same way, no dif, except that xp pro may actually give you more trouble with poser because it may have more stuff running in background. Use XP Home Edition unless your networking your home. Make certain you learn how to control your computer so that when your running poser you can turn off excess programs running in background that will also affect poser. Have fun.