11 Ways to Optimize Performance in Unity 6 You Probably Didn't Know

 

I know, one of the most challenging and important tasks as a game developer is to optimize performance in Unity 6. The problem is that it’s not always clear what causes the lag or stutter. Perhaps after some deep diving into the issue, you come to find out that a texture was of too high a resolution. Or that there were too many unnecessary vertices on a 3D model. Or maybe your scripts are not optimized.

Even if your game is running flawlessly on your machine when play testing, it may struggle on another for no apparent reason. Below, I’m going to mention some of the most common ways to optimize performance in your game development project in no particular order. Some are easy to implement, others may require a bit more research. Some may not even apply to your current game development project at all, but in any case go over it and make sure your game is as optimized as can be (you may need it for your next project!).

1. Use Object Pooling

Instead of constantly instantiating and destroying objects, reuse them through an object pool. This reduces garbage collection spikes and improves runtime performance, especially for frequently spawned objects like bullets or enemies. Here's how to do it with a bullet for instance:

public class BulletPool : MonoBehaviour
{
    [SerializeField] private GameObject _bulletPrefab;
    private Queue _pool = new();

    public GameObject GetBullet()
    {
        if (_pool.Count > 0)
        {
            var _bullet = _pool.Dequeue();
            _bullet.SetActive(true);
            return _bullet;
        }

        return Instantiate(_bulletPrefab);
    }

    public void ReturnBullet(GameObject bullet)
    {
        bullet.SetActive(false);
        _pool.Enqueue(bullet);
    }
}
  

Pros:

• Reduces runtime allocations
• Smooths gameplay by avoiding garbage collection spikes

Cons:

• Requires management logic
• Needs more memory up front

2. Use Object Culling

Disable or unload objects that are far away from the camera or outside the player’s view. Unity’s built-in frustum culling and occlusion culling help, but you can also implement custom distance-based culling.

Pros:

• Reduces draw calls significantly
• Can be combined with Level of Detail (LODs)

Cons:

• Setup and tweaking required
• Improper culling may cause pop-in, which looks weird in any game

3. Use Level of Detail (LOD)

Swap high-poly models with lower-detail versions at a distance. Unity’s LOD Group makes this straightforward.

Pros:

• Huge performance savings in 3D games
• Easy setup with LOD Groups

Cons:

• Requires extra assets/models
• LOD popping can be noticeable without blending

4. Cache Component References

Avoid calling GetComponent or similar expensive lookups in Update(). Cache them once in Awake() or Start().

private Rigidbody _rb;

void Awake()
{
    _rb = GetComponent();
}
  

Pros:

• Simple and effective
• Prevents hidden performance drains

Cons:

• Component needs to be on the same game object

5. Reduce Physics Complexity

Use primitive colliders instead of Mesh Colliders when possible. Disable unnecessary physics calculations by adjusting collision layers and using isKinematic on objects that don’t need simulation.

Pros:

• Improves physics performance drastically
• Collision layers give fine control

Cons:

• More manual setup required
• May reduce physical accuracy

6. Batch Draw Calls

Use static batching, dynamic batching, or GPU instancing to reduce the number of draw calls. Fewer draw calls = faster rendering.

Pros:

• Big boost for rendering performance
• Unity handles some batching automatically

Cons:

• Static batching increases memory usage
• Dynamic batching has vertex count limits

7. Use Light Baking

Instead of using real-time lights everywhere, bake lighting into lightmaps for static objects. Combine with mixed lighting for balance.

Pros:

• Massive runtime performance boost
• High-quality visuals with baked GI

Cons:

• Baking takes time and uses up disk space
• Not suitable for dynamic environments

8. Optimize UI Rendering

Avoid excessive canvas rebuilds by splitting UIs into multiple canvases and minimizing frequent updates is one of the most common ways to optimize performance in Unity 6. Reuse UI elements instead of recreating them.

Pros:

• Improves UI responsiveness
• Scales better for complex menus

Cons:

• Requires extra structuring
• More planning during UI design

9. Profile and Analyze

Always use the Unity Profiler and Frame Debugger to find actual bottlenecks. Guessing wastes time. Measure, then optimize.

Pros:

• Targets the real performance issues detected in Unity

Cons:

• Steep leaning curve to understand all the features of the Unity profiler

10. Pool Coroutines and Avoid Excessive Updates

Too many Update() calls slow things down. Consider central managers or coroutines that are reused, and avoid spawning new coroutines every frame.

Pros:

• Reduces overhead from excessive Updates
• Cleaner structure with managers

Cons:

• More complex to manage

11. Impostor Rendering Technique (URP)

Last, but certainly not least: Impostors, a new way to optimize performance in Unity 6. An impostor at its core is like a 'cheap stand-in' for a complex 3D model. There are a few ways this can be done. For instance, 2D billboard impostors, which is basically a flat plane with a texture of the object that is facing the camera. There's also a 3D impostor, which is a very low-poly mesh that has baked textures and simplified shading. Finally, there's a mix between the two: hybrid impostors. Those feature low-poly geometry with baked textures, sometimes combined with normal maps for lighting.

Pros:

• Drastically reduces draw calls
• Reduces GPU vertex and pixel load
• Makes rendering large scenes more doable, like forests, cities, or crowds
• Works very well in combination with GPU instancing and occlusion culling

Cons:

• Flat or 'fake' appearance if not placed well in your scene
• If your baked textures are too small, distant objects can look blurry or pixelated, so there are texture resolution limits with impostors.
• Baked normals or lighting might not perfectly match dynamic lights, causing objects to look weird (due to lighting mismatch).

If you want to learn more about impostors in Unity 6, my friend Matt (SpeedTutor), made an excellent YouTube video about the concept and its implementation.

Wrap up:

Alright, these are all the ways to optimize performance in Unity 6 that I can come up with. Do you use any of these techniques in your Unity projects? Did you learn something new? Or do you know another performance trick that works even better? Share your thoughts in the comments below!