Okey, I’ve got the right techincal terms I wanted to mean to say, so it is:
Does glDrawTex create an entire new batch for each call to it, or just one for the entire frame?
In other words: is glDrawTex CPU bound or GPU bound?
Or: is my question implementation/device specific?
Pretty much all questions on performance are implementation specific.
But drawing lots of small rectangles with glDrawTex is likely CPU limited. In this case it is better to put all rectangles into one vertex array, use a texture atlas, and draw them all with one draw call.