GTX 690 has LAG 0.0

[Tigerace2712]

So, basically, I just got a gaming PC for my birthday, it's a really good one, im not allowed to get a new one for the next three years haha.

Here are the specs:
32GB Corsair Vengeance RAM
GTX 690 4GB
I7 3970 Extreme Edition 3.50GHZ 12 Core
2 TB d drive and a 112ssd drive for windows.
1200W power supply or something.
Water cooling + 3 other fans.

So there I was, expecting it to run greatly. I check SLI/Multi Gpu is enabled, it is, so I download League of Legends.
Once in a game, I set all the graphics to high . .
In the beginning, it ran at a solid 60 FPS.
But the more action that was going on (Spells, combat etc) my FPS dropped to 35-40.
I don´t think this is normal, I mean, coem on, its a 690
I can run bf3 on 110FPS.
Could someone please tell me what the hell is going on!
P.S LoL is not the only game that lags, the following games ive tested have all run at arounf 40 FPS:
Borderlands 2
War of the Roses
Hearts of Iron III
Mount n´ blade with fire and sword - WTF

The following games ive tested have ran at a solid 60/higher:
BF3
WoW
WoT
Amnesia TDD
Arma II - 3D Resoluton at 100%, not 200%, because 200% == Dead PC
Cod WaW
Empire Total War
Legend of Grimrock
Civilization V

Someone tell me what all the lag is about in the other games, like on Mount and blade WTF??

Thx for your time

 

[AMD Radeon]

afaik, some games are not optimized for multi GPU....

 

[Tigerace2712]

So, I need to turn it off? For those games listed?

 

[Tigerace2712]

afaik, some games are not optimized for multi GPU....

So I need to switch SLI/Multi GPU off? Should I then set the GTX 690 (B) for just PHysx when playing, or just leave it sitting there?

 

[Tigerace2712]

Best answer selected by Tigerace2712.