Here are several tips to help you make instance playback faster:
If you are using complex geometry for the particle instance, or just many instances in a simulation, you can optimize the display by using other shapes to display them in the viewport.
To do this, select a shape, such as boxes or rectangles, from the Display As list in the point cloud's Particle Display property editor (see Setting the Particle Display). The shape you select will be scaled according to the geometry's bounding box.
You can also create a lower-resolution and unanimated version of the instanced geometry as a stand-in (proxy) for more complex, animated instances. Then use an If node to switch between the stand-in and the real instance geometry when you want to use it.
For better performance, textures are not displayed on individual instances in the viewport, but they will be rendered.
If a volume shader is connected to the particles in the render tree (such as the Particle Volume Cloud shader), the instance shapes are ignored and the particle data is instead rendered using the volume shader. You need to render particle instances with a surface shader.
There are several types of display attributes to help you visualize the instances in the viewport if you're working in wireframe mode or a using low-resolution version of the instance geometry. The Orientation and Point Velocity attribute types may be particularly useful to help you see how the instances are oriented and moving. See Creating Particle Display Attributes for more information.
