Models Lagging Play Mode?

I think my blend models are lagging play mode. I looked up a few other questions and they said I should keep my poly count low if possible so I did what I could. I tested my script with a ship (55 verts, 102 edges, 47 faces) and I believe tris is triangles so 102 triangles? And play mode seems to have a really rough time updating. I also tried it with a cube and, while it seemed to run smoother, still ran pretty slow and "chuggish". Am I asking for too much with my models? Or my script?

I'll add my script just in case it's causing an issue using UnityEngine; using System.Collections;

 public class PlayerControls : MonoBehaviour {
     
     private float speed ; // Make private later
     private float baseVal = 0.01f ;
     private float rate = 50.0f; // Rate at which speed increases
     private float MIN_SPEED = 0.0f ; // Redundant in case of speed, but good practice 
     private float MAX_SPEED = 6.0f; // Maximum speed 
 
     void Update(){
 
         if(Input.GetKeyDown(KeyCode.W)) speed += baseVal * rate ; 
         if(Input.GetKeyDown(KeyCode.S)) speed -= baseVal * rate;
         if(Input.GetKeyDown(KeyCode.Space)) speed = MAX_SPEED ; 
         if(Input.GetKeyDown(KeyCode.X)) speed = MIN_SPEED ; 
 
         if(speed < MIN_SPEED) speed = MIN_SPEED ; 
         if(speed > MAX_SPEED) speed = MAX_SPEED ; 
         // Since speed is a magnitude, it should never be negative. 
 
         Vector3 newVel = new Vector3(speed, speed, speed) ;
         GetComponent<Rigidbody>().velocity = newVel ;
         Debug.Log ("Speed:" + speed);
     }
 
 }