The first post should be fairly obviously the relevant bit...
Now, the addressing limits I knew about.
The gpu sucking up gigantic amounts of the addressing I knew about.
I did NOT know that dx9 etc also replicated the gpu memory into system memory, further depleting the pool. Ugh, and no damned wonder.
Solid article. I hear a lot of these things, even among tech people, incorrectly cited. "There's no real version between the 32 bit and 64 bit version of XYZ" comes up a lot. I can tell you that I personally like using more then 3GB of RAM, so 64 bit is the only way I roll....