Do you know if there are compatibility problems between elementary OS (Freya) and NVIDIA GTX980? I've installed elementary OS but it's hard to use it. I've to plug two screens (one on the GTX and the other on on the motherboard's HDMI output). The MB BIOS is displayed via GTX's screen, and when elementary OS boots, it switches on the MB's screen. I don't know why.
Try using non open source drivers. Either obtained under "proprietary settings" in Software centers preferences, or from the geforce website. I may note that I've personally noticed that installing prop. drivers is a total asspain.
You should be able to chose the proprietary driver in the settings just like Logan said. If you are not afraid of using ppas, you could go and install the latest official Nvidia driver by following this guide: OMG!Ubuntu guide