I am having a problem when attempting to scale point sprites. As the scale size increases, my frames per second can go from 30 FPS to about 2 FPS.
I am using point sprites to display icons on a map. There can be 100K to a million points. With 1 million points, performance is acceptable unless you attempt to increase the size of the sprite.
I have a vertex/pixel shader that colors, rotates, and scales the points.
The textures are small icons, typically 64x64 or smaller and are compressed dxt5.