Im slowly modding my PC more for gaming, apart from the graphics card i need to get a 64 bit OS in order to have more than 3GB of ram. I was thinking of getting Vista Ultimate OEM. Heres the dealio, i was not a fan of vista home P or B because i was under the impression that this was like XP home in the way that you cant do what you want with certain files.
I was also under the impression that vista ultimate was more like XP pro in the way that you can change the files.

Is this true and to what extent can you slim vista down to get rid of all the fancy stuff which i really do not need/want. I want it to use as little CPU/memory as possible,

Thank in advance..

If you are planning on gaming, i dont recommend Vista 64bit. (compatability issues) but if you have your mind set on it. There isnt really much you can do to slim down Vista.

well what would you recommend in order to use more than 3GB of RAM.

Im guessing that the maximum RAM on 32 bit vista is 3.25 or something like XP.

Yes you are correct about 3.25gb.
There's plenty you can do with Vista to make it less resouce hungry. Turn off the Aero effect (waste of resources, never use it anyway), disable plenty of services. I use Home Premium and I find it perfectly fine in terms of resource managment.

My main issue was being able to use more than 3 GB of RAM.