I render some lines with alpha values into an FBO. Because I play a lot with alpha, I need the alpha channel to have more detail than RGBA8. For example, RGBA32F works like a charm.

As I have only a Quadro GPU to test. Is there a general advice on which FBO format works best (in terms of speed) on most cards?

1. Would there be a benefit in using RGBA16F, RGBA16 etc.?
2. What formats can I expect a GPU to support?
3. Is RGBA32F a regular feature for a GPU not older than 5 years?