4K Playback Unstable

I'm currently using the newest version of Resolve but am unable to playback (and therefore edit) my footage. I'm admittedly a novice with Resolve, but I've tried everything I can find to get my footage to playback smoothly. My system is strong enough with an i7-5820k, 2X GTX 980s in SLI, and 16GB of RAM but I can't get playback to exceed 16-35 fps. I've tried the render caching but it made no difference. Any advice would be greatly appreciated!

Thanks!