Comment 8 for bug 1070760

I've been able to test on a Nexus 7. Xorg fully occupies a single core during heavy cairo drawing while Onboard sits mostly idle and waits for drawing operations to finish.
The main culprits are gradients and drop shadows, turning these off makes themes somewhat usable.
The default backend for cairo seems to render purely in software, single threaded to boot, and it's simply too slow to do what Onboard needs. I'm going to run some experiments to see what we can do and possibly bypass cairo.