Due to some GPU and/or plug-in limitations, you may find that-- if you are in Acceleration mode-- that you will get switched into Direct mode.
Since this switch can sometimes occur for performance optimization based off the GPU, you may find better results if you switch to CPU mode.
The primary instances this switch will occur automatically include:
- Using an animated movie/file type for the Sprite/Texture Polygon
- Applying different particle blend modes to different systems
- Trying to use Depth of Field with a Sprite/Textured Polygon
- Trying to use Depth of Field with a Square particle
- Using either 'Normal Add over Life' or 'Normal Screen over Life' as the particle blend mode
- Using Shadowlets with anything other than ‘Normal’ set as the blend mode for the particle
A last potential issue is that star particles may show parity issues when in streaming mode, in which case you should switch to Direct or CPU to workaround the issue.