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# speedFactor

A multiplier for the speed at which SceneKit runs the particle simulation. Animatable.

```
var speedFactor: CGFloat { get set }
```

## Discussion

Use this property to speed up or slow down the overall behavior of a particle system without changing the many individual properties (such as [`acceleration`](/documentation/SceneKit/SCNParticleSystem/acceleration), [`particleAngularVelocity`](/documentation/SceneKit/SCNParticleSystem/particleAngularVelocity), and [`particleBounce`](/documentation/SceneKit/SCNParticleSystem/particleBounce)) that affect the motion of particles.

The default value is 1.0. Lower values slow down the effect; higher values make the effect run faster.

You can animate changes to this property’s value. See [Animating SceneKit Content](/documentation/SceneKit/animating-scenekit-content).

---

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