With the introduction to Unity 5 there comes some api changes. Specifically this foot note was interesting “[2] in Unity5 we also cache the transform component on the c# side, so there should no longer be a performance reason to cache the transform component yourself.”

I decided to test it out by writing a few performance test scripts and comparing performance numbers. Below is a screen shot of my results along with the scripts used.

As you can see caching a reference to the transform component in the Start method then using that reference is still faster then calling “this.transform” directly albeit only slightly by about 10-20 ticks. And calling “this.GetComponent<Transform>()” is almost twice as slow.

The code for the PerformanceTesting class is availible here.

TransformCachedGetComponentPerformance script

    using UnityEngine;

    public class TransformCachedGetComponentPerformance : MonoBehaviour
    {
        private Transform reference;

        /// <summary>
        /// Awake is called when the script instance is being loaded.
        /// </summary>
        public void Awake()
        {
#if PERFORMANCE
            var perf = PerformanceTesting.PerformanceTesting<string>.Instance;
            perf.Create("UnityTesting/TransformCachedGetComponentPerformance/Update");
#endif
        }

        /// <summary>
        /// Start is called just before any of the Update methods is called the first time.
        /// </summary>
        public void Start()
        {
            this.reference = this.GetComponent<Transform>();
        }

        /// <summary>
        /// Update is called every frame, if the MonoBehaviour is enabled.
        /// </summary>
        public void Update()
        {
#if PERFORMANCE
            var perf = PerformanceTesting.PerformanceTesting<string>.Instance;
            perf.Start("UnityTesting/TransformCachedGetComponentPerformance/Update");      
#endif

            var rnd = new System.Random();
            this.reference.localPosition = new Vector3(rnd.Next(-3, 3), rnd.Next(-3, 3), rnd.Next(-3, 3));

#if PERFORMANCE
            perf.Stop("UnityTesting/TransformCachedGetComponentPerformance/Update");
#endif
        }
    }

TransformGetComponentPerformance script

    using UnityEngine;

    public class TransformGetComponentPerformance : MonoBehaviour
    {
        /// <summary>
        /// Awake is called when the script instance is being loaded.
        /// </summary>
        public void Awake()
        {
#if PERFORMANCE
            var perf = PerformanceTesting.PerformanceTesting<string>.Instance;
            perf.Create("UnityTesting/TransformGetComponentPerformance/Update");
#endif
        }
        
        /// <summary>
        /// Update is called every frame, if the MonoBehaviour is enabled.
        /// </summary>
        public void Update()
        {
#if PERFORMANCE
            var perf = PerformanceTesting.PerformanceTesting<string>.Instance;
            perf.Start("UnityTesting/TransformGetComponentPerformance/Update");
#endif

            var rnd = new System.Random();
            this.GetComponent<Transform>().localPosition = new Vector3(rnd.Next(-3, 3), rnd.Next(-3, 3), rnd.Next(-3, 3));

#if PERFORMANCE
            perf.Stop("UnityTesting/TransformGetComponentPerformance/Update");
#endif
        }
    }

TransformFieldPerformance script

    using UnityEngine;

    public class TransformFieldPerformance : MonoBehaviour
    {
        /// <summary>
        /// Awake is called when the script instance is being loaded.
        /// </summary>
        public void Awake()
        {
#if PERFORMANCE
            var perf = PerformanceTesting.PerformanceTesting<string>.Instance;
            perf.Create("UnityTesting/TransformFieldPerformance/Update");
#endif
        }

        /// <summary>
        /// Update is called every frame, if the MonoBehaviour is enabled.
        /// </summary>
        public void Update()
        {
#if PERFORMANCE
            var perf = PerformanceTesting.PerformanceTesting<string>.Instance;
            perf.Start("UnityTesting/TransformFieldPerformance/Update");
#endif

            var rnd = new System.Random();
            this.transform.localPosition = new Vector3(rnd.Next(-3, 3), rnd.Next(-3, 3), rnd.Next(-3, 3));

#if PERFORMANCE
            perf.Stop("UnityTesting/TransformFieldPerformance/Update");
#endif
        }
    }