Blender doesn't render via F12 only in the 3D View

Yes that is right. Well to be all honest when I have a specific load it shows me an error that my CUDA ran out of memory. But not that it also needs hours to reprocess before rendering while in when I switch the 3D view to rendered it speeds up like crazy. I am guessing that there might be some options but I seem to be to incompetent to find them. Even the rendering process is way faster while not seeming to be any better. I also have to admit I am pretty much a noob to blender, haven’t done to much in here and this was my first real work, so my skills may vary.

Here is a picture to show what I’ve got trough the 3D Rendered, I toned everything down so far that Blender doesn’t seem to crash at all:

Don’t tell me I know I have still to change some parts and make something right with the fur (And yeah it really doesn’t look good without the whole body fur). If you whish I of course can upload the blend file. Just for some Information I have about a million triangles in this scene if that should be any problem.

Also currently I am rendering with an GTX970, also I am using an AMD FX8120 with 8GB 1600mhz DDR3 RAM, but next week will be an upgrade to an i7 6700k with 16gb 3000mhz DDR4 ram.

Rendering in the 3D view and via F12 is differently handled - some effects are only rendered in the “real” render mode and not in the 3D “preview” rendering.

But unfortunately I have no clue how to solve your problem.
You could try rendering with CPU to test if the problem just happens while using your GPU. This will perhaps provide others the needed info to solve the error…