Let's start off with the basics: Xorg.0.log, dmesg and a system profile of what is happening when it is slow. And narrow down the complaint, for instance are the measurements you made in parallel with other system activity or after you shut them down?
Also please do try running these tests with a non-OpenGL compositor (i.e. not unity or gnome-shell) to rule out the lack of acceleration from mesa being a limiting factor.
Let's start off with the basics: Xorg.0.log, dmesg and a system profile of what is happening when it is slow. And narrow down the complaint, for instance are the measurements you made in parallel with other system activity or after you shut them down?
Also please do try running these tests with a non-OpenGL compositor (i.e. not unity or gnome-shell) to rule out the lack of acceleration from mesa being a limiting factor.