Re: I May go Linux
You can google those questions. Linux still has upgrades it's just they are cheaper, smaller and more frequent. For a beginner I suggest a live CD. It will give you a taste for a minimum of learning. For some distros there is plenty of learning while others strive to be simple and easy (ie they make the decisions).
As for games I'm pleased you have a nVidia card. The UTs/Dooms/Quakes will play native on it. The adventurous try windows emulation with cegeda. Ymmv.
Performance wise games might go just a tad slower. Nothing to worry about. Desktop apps go faster because windows is a memory hog and keeps on swapping.
64 and 32 bit apps can coexist on linux. And in different ways btw. I suggest you dual boot windows/linux for a while. Good luck.