Dual Graphics card SLI Problem

Hello Forum, im CrazyKilla

I have Dual GTS 450s which work very nicely, although performance isn't too great, at first i didn't know how to enable SLI, but then i found this in NVIDIA Control Panel



The problem is, Every time i start up my PC, i have to open up the drop box, and change from GTS 1 to GTS 2, or GTS 2 to GTS 1, then dedicate that card to PhysX, that enables SLI, but only some of the time,

Why do i have to switch what card is Dedicated to PhysX every time i start PC to enable SLI? i know if its enabled or disabled because i have a program called TechPowerUp GPU-Z that shows if SLI is enabled, and also if SLI is enabled my gaming performance increases a lot,

So you have to reset the options every time?

It might be worth uninstalling / re-installing the video drivers and doing a custom installation. Don't install: the updater, the 3d vision drivers, hd audio. Basically you only want the video driver and physx.

During the process, there is an option checkbox to "Perform a clean installation" -make sure you enable that. It basically sets everything to defaults during installation.

As for the Physx dedication - leave it to Auto.

Hook up both screens to card number 1

If i put both monitors to card number 1, it pritey much just says that i only have 1 card, and doesn't allow SLI at all,
As for the Reinstalling drivers, done, about 6 times before this post, but still hasn't fixed it,
Ill try leave PhysX dedication to Auto and see if it keeps SLI on after restart,
Also i did install drivers including clean isntallation about another 8 times, not fixing