Mambatron

Hello! I just wanted to get some opinons maybe someone knows the answer. I am running Sim City 2013 on a single GTX 690 (Which has 2x GPUs in it). Sim City 2013 puts all the load on one gpu in the GTX 690 that usually stays above 90% load and my temps on that 1x GPU go around 70. Not that this is a terrible thing but most games I play use both GPUs on my GTX 690. I rather the game split the load onto each GPU. I am gaming on a 1920x1080 120hz monitor by the way. Any feedback would be great.