Can anyone please explain what is happening?
The only difference between the first run and the second is one single “step” in the zooming of the scene.
Why does the gpu latency spikes like that?
Why the fps drop?
Rasterizer, services, outside, everything changes dramatically
You get closer to human, more pixels of higher poly mesh(human) gets rendered, human rendes worse than floor. And your GPU renders it slower than floor so, the more pixels of the most complex and high poly object in scene, the more GPU latency. Any high-poly meshes when close to camera(much pixels on screen) will slow down your GPU, but the further they are, the less pixels and less calculations for much vertexes, only low poly plane gets left and GPU does it much faster.
I tried using a simple 2x2x2 cube instead of the human. The only change is that rasterizer now stays at 8% but gpu latency is still at 60% - 65%, fps goes down by 15 on every zoom step for a grand total of 20 - 30 fps on full screen.
Apparently is not the human model.
I don’t think it has to do with any model in particular per se, but rather the zooming itself, as adrian kind of hinted at. As you zoom in, the game has to render more pixels of the game scene, which can slow things down. You’d probably see the same issues if you played the game in the standalone player - it would slow down more the larger the game window is.
What kind of GPU do you have?
AMD Radeon HD 8400.
I made a zoom function.
I put 32 spotlights with shadows and x16 AA. everything remains the same. It doesn’t matter if there’s a single light or a bunch of them. This layer only, no shadows, shadows, no AA, AA, a cube, a human, zooming in and zooming out.
As long as the “playing” screen is a certain size it stays at 59 - 60 fps (even when zooming in for more pixels or out for more lights). As soon as I make the screen a little bit bigger then GPU latency peaks and everything bogs down.
Your card may not support very large resolution. AMD has also some problems with Blender, Blender better likes NVIDIA!
I am aware that blender “doesnt like” amd, but there’s got to be something else going on here, I mean, look at those images, is not alien isolation or diablo 3 that im making, any crappy gpu should be able to handle 5000 polys and a few lights without turning the game into a powerpoint presentation
Have you tried updating your graphics card drivers?
Have you tried different versions of Blender?
Looks like you’re using GLSL lighting, right? I assume the problem disappears if you switch to Multitexture mode?
I updated the drivers to the latest release and I’ve tried it in blender 2.6 up to 2.74.
In multitexture mode the problem disappears, everything looks white, just white, like a new image file, picture a 21 inches single white pixel if you will 
