Re: Half-Life 2 - non-official DirectX9 patch
It won't magically make your FPS twice as high again. If that's what you think/expect you are in for a dissapointment.
What it does appear to do is substantially raise minimum frame rates and make the entire game feel a lot smoother than it used to.
This is on my XP2400+. I've only just upgraded to a3200+ and haven't gotten around to testing with it yet.