Nvidia is "famous" of "tweaked" drivers. They desperately try to "better" their products by dupious methods. Don't you love the idea of making drivers to a specific software/game to get better results in speed tests!
And Nvidia knows that nobody is using old games/progs and only the stupid try to use new games/progs before nvidia launches a driver set specially tweaked for them
What a sad company.
Everybody does this. It'd be absolutely ridiculous and foolish not to. It only becomes a problem if the output is changed (which all major graphics companies are suspect to). You're awfully short-minded.
Regarding this issue, on a Winblows box with SW drivers, no issues. On a Winblows box lacking SW drivers, no issues. Both are nForce2. Never any issues on Gentoo machines, running nForce / nForce2.