The older PhysX games I've tried (e.g. Two Worlds) run fine with the last legacy driver installed alongside the latest normal PhysX version without any tinkering; do you know if any games other than Infernal require the workaround described on Ageia PhysX?
Topic on User talk:Sigma 7
The difficulty with Aegia PhysX was running the legacy and modern versions side-by-side, and manually adjusting drivers was the only option until NVidia released the legacy versions of PhysX. It was necessary in the past, as there was no official workaround. While the latest driver update fixes that, the page may still be required in case something messes up the game.
The proper test is running Two Worlds, followed by a modern game such as Metro 2033. Both of those require different versions of PhysX drivers that aren't compatible.
In case of Infernal, the official drivers still don't work, as it didn't include v2.5.2 even in the legacy pack. There may be other games like that - as such, the general workaround should still be visible in case something fails.
Thanks for clarifying the problem and updating the pages. :)