---
title: ProcessInfo.ThermalState.serious
framework: foundation
role: symbol
role_heading: Case
path: foundation/processinfo/thermalstate-swift.enum/serious
---

# ProcessInfo.ThermalState.serious

The thermal state is high.

## Declaration

```swift
case serious
```

## Discussion

Discussion The system takes moderate steps to reduce thermal state, which reduces performance. Fans are running at maximum speed. Reduce usage of resources that generate heat and consume battery, for example: Reduce or defer I/O operations, such as networking and Bluetooth Reduce the requested level of accuracy for location Reduce CPU and GPU usage by stopping or deferring work Reduce the target framerate from 60 FPS to 30 FPS Reduce the level of detail in rendered content by using fewer particles or lower-resolution textures For more details on how to reduce your app’s use of these resources, see Energy Efficiency Guide for iOS Apps and Energy Efficiency Guide for Mac Apps.

## See Also

### Constants

- [ProcessInfo.ThermalState.nominal](foundation/processinfo/thermalstate-swift.enum/nominal.md)
- [ProcessInfo.ThermalState.fair](foundation/processinfo/thermalstate-swift.enum/fair.md)
- [ProcessInfo.ThermalState.critical](foundation/processinfo/thermalstate-swift.enum/critical.md)