Rendering a plane is dropping 10 fps

Hi all!

I have a setup with 2 high-poly models and a floor/plane (not a terrain, just a rectangle) with a texture and a skybox

I realized that if the camera barely see the floor the fps go higher, on the other side if the camera is from top and see the floor the fps drop by 10

Not looking at the floor = 40 fps, looking at the floor = 30 fps (please look at the images below)

I'm using the Mobile/Difusse Shader

I thought it was a rasterization issue, so I already tried modifiying the shader to skip the ztest and the zwrite and drawing it first, but still the same

I decreased the Texture size to 256, still the same

No skybox still the same

What seems weird to me, is that without the floor/plane, doing the hardwork of rendering the models it gives 40fps but just adding the 6 vertex or so from the floor it drops 10 fps, that's what I think is a rasterizer issue because when the plane floor covers the the whole screen it visits all the pixels... still 10 fps drop seems too much

Any ideas?

Thank you

J Rdz

Camera looking front, no other models (usually 59-60 fps)

Camera looking at floor ( 51 fps)