Odd happening with sata HDD smart status on speedfan

[Comdrpopnfresh]

I recently put together my current computer. My two harddrives never showed up on speedfan for smart status or temps.

After disabling all ide controllers and settings (dma + pretech), removing my x-fi card from my system, reseating my gfx card to a different slot, and uninstalling x-fi components, intel cpu identifier, and some driver-checking program it all of a sudden showed up...

Before my changes, was there something causing a problem or conflict, that was resolved by my actions? I'm really interested, because it happened without my trying to remedy it. Typically when I fix or change something with a goal in mind, I usually do one thing at a time, but since I wasn't aiming to have my drives show up, I did all those things at once- so I'm left with no clue to what did it.

 

[Comdrpopnfresh]

after installing Asus's newly posted nvidia platform drivers, my drives disappeared. I'm inclined to take this as indicating that switching from the nforce sata controller drivers to the generic vista ones made the drives show up.

So:
Is there any performance gain through having the nforce drivers vs the vista ones?
If smart monitoring is enabled in bios, and the nvidia drivers make the smart status disappear in vista, would a problem smart would catch be alerted to me by bios?