Trying to Enable SLI

[Curbkiddytech]

I took out my granpa's 470 GTX because it was causing his computer problems. I got the idea of running it in SLI with my 470 GTX tonight and gave it a try. I have both cards powered because the fan is running on both, the bridge is connecting them as well. My mobo is SLI compatible and I have the latest video drivers. However, there should be a setting in the Nvidia Control Panel where I can officially enable SLI but I can't find it which makes me wonder if something is wrong? A point in the right direction would be appreciated.

P.S. In the advanced video settings it shows there is 2555MB of Video Memory available when the 470 only has like 1280 which means the OS sees the second card right?

 

[Slaymate]

Have you re-installed the drivers since adding the 2nd card?

 

[Curbkiddytech]

Yeah sorry for that post, after messing around a while after that I figured out how to enable SLI. My only question is why I'm not seeing a performance boost on some of my games. For example, Dragon Age 2 runs terrible with very high settings in DirectX 11. When I crank it down to high on DX11 it runs fine, and even better when on DX9. With the second graphics card in I thought that problem would go away, but it still sucks on very high. Also the amount of usable memory didn't increase when I tried cranking up the settings in GTA IV. Can you explain why my games aren't improving performance wise?