I am not sure if I have a bug or doing something wrong, but here I go…
If I use the GL_GENERATE_MIPMAP method to make mimaps, my particle textures are fine regardless if I use compression formats or uncompressed, if I use glGenerateMipmapEXT() and no compression some of the particles show lines in the texures and if I use compression they disappear? I haven’t tried this without using the PBO to stream the data in, but doubt that would make a difference seeing how it works with GL_GENERATE_MIPMAP so the code is sane. This is on Vista and GF8800GTS with latest drivers.