Lower Frame rate for less polys ?

Hello everyone,

I am trying to create a very simple space shooter. I am importing premade 3D spaceship models and I have the following issues:

When I import spaceships made of 4k polyogons, I can can reach ~250k polygons before my frame rate drops to 350.
However, when I import a single model of another spaceship made of 50k polygons, my frame rate drops to 100.

Here are the details.

Case 1 (350 fps):

Main thread: 2.8 ms 
Renderer: 0.1 ms
Draw calls: 56
Saved by batching: 0
Tris: 247k
Verts: 152k
Used textures: 3 - 128 KB
Render textures: 0
VRAM usage : 9.7MB to 10MB (out of 0.97 GB)
VBO total : 16 - 0.5 MB

Case 2 (100 fps):

Main thread: 8.7 ms
Renderer: 2.0 ms
Draw calls: 84
Saved by batching: 273
Tris: 41.9k
Verts: 53k
Used textures: 6 - 470 KB
Render textures: 0
VRAM usage : 9.3MB to 12.9MB (out of 0.97 GB)
VBO total : 346 - 3.1 MB

I also have another problem linked with this issue:
My lateral movement command is:

transform.Translate(Vector3.forward * LateralSpeed * Time.deltaTime, Space.World);

However, my spacesheep speed decreases with the framerate. Any idea why I have this?

Thanks!

Make Prefab for all the Objects in Scene Make Sure They are Marked Static and MOST IMPORTANT
Change Vsync to NoVsync **Thats the most frequent problem with low poly assets **