Okay i run a Nvidia GTX 680 2Gb card and my render of the bunny was a lot heavier than yours.
I DO NOT have the 378.78 driver version i have the one prior to that and i can render fine.
I suggest you roll back your drivers for your GPU to the previous version and try re-rendering then.
Not sure why CPU would cause a crash though but get back to me on what happens after making this change.
1,803,353 Verts
2,011,314 Faces
2,268,029 Tris
128 samples 1080p 75%
200 light paths
16 * 16 tiles
CPU rendered (My Gpu does the nvidia cuda memory error too)