Movement cutting frames in half?

I'm experiencing some bizarre and massive frame loss when moving my character. The weird thing is, this frame loss only occurs when the character is moving either forward or backward. My first thought was that the animation for walking was more intense than the animation for turning, so I changed them both to be the same. Frame rate is still getting cut in half. I thought it might have to do with the camera following the character and having to draw new terrain and objects. However, rotation still causes new objects to be drawn, and the frame loss is normal when rotating. Additionally, I created multiple versions of my character prefab in the scene, but only attached the camera to one of them. They all respond to the input the same way, and this causes frame rate to be cut in half for each character copy, down to a ridiculously low number considering I've only got about 10 low poly objects in my scene.

Our movement code is a carbon copy of the 3rd Person Controller script, except with all the jumping mechanics removed.

We use the Input.GetAxis() function to recieve movement input. It only experiences massive frame loss when Input.GetAxis("Vertical") is receiving information. This leads me to my final conclusion. The W and S keys are computationally more expensive than other keys. Lol, this is not a satisfactory conclusion.

Anyone have a better idea of what's going on?