Odd picks in profiler with simple scene in unity

HI, I need some help optimizing my game. I have spent last 3 days digging around with no luck. I have noticed really odd results in the unity profiler so, I have created a simple scene with just a cube and a camera, and again, really odd results. Could anybody have a look at this sceenshots?:

http://postimg.org/image/v2pxzteqb/

http://postimg.org/image/nb9819akz/

http://postimg.org/image/wghkv4dzn/

You will see some significant peaks that make the frame time too high (30fps sometime or less). Scene hasn't any script, no colliders, no rigid bodies (notice the Physics simulate % in one of the shots).

Could anybody explain what is happening?

PD. Target platform is Android. This are taken from a Nexus 4 device.

Thanks in advance.