Hey. I'm planning on buying a desktop, but I'm a little confused as to the difference between 32-bit Vista and 64-bit Vista, and exactly what those differences entail.
Now, I think the technical difference is the size of the memory bus. Well, if I'm right, I'm not exactly sure what that means. Does it mean that the address of a memory location can be 32/64 bits long? Or does it have to do with accessing memory? Or both? I could use some clarification on that.
Now, I've also heard that one of the results of this is that a 32-bit OS can only deal with up to 4GB of RAM. However, I've also heard 3 GB. An article I read said that the limit was 4GB, but some computers register less than this because some of the memory is used for address mapping. Is the whether you have a 32/64 bit OS relevant to this space taken up for address mapping?
And lastly, I heard that software designed for a 64-bit OS won't work on a 32-bit. That makes sense, but I'm unclear as to whether software designed for a 32-bit OS will work on a 64-bit.
Please and thank you.