I do have a SandyBridge desktop. This system is a bit special as it is the one in which I can run a discrete card in direct comparison to the ingrated processor graphics, i.e. run both GPUs simultaneously (but not yet co-operatively). In this system I put a Radeon HD5770 which at the time was a mid-range GPU offering good value for performance. So how does Cairo fare on this box? In particular are the DDX drivers any better than pixman, the backend for Cairo’s software rasteriser?
Once again the white baseline in the centre represents the performance of the image backend, how fast we expect to be able to render the contents ourselves. Above that baseline, the driver is faster; below slower, laggy and power hungry. This is quite a busy graph as it compares the performance of the propietary fglrx driver and the open-source radeon driver along with the alternative acceleration methods for the integrated graphics. I’d recommend viewing at full size, but the gist of it is that in many cases the propietary driver lags behind the open-source effort. Neither are truly comparable to just using the CPU and only the open-source effort is ever faster. In contrast, we have the integrated processor graphics. Even this GT1 desktop system (only half the GPU capability of a GT2 system such as found on mobiles and on a few desktop chips) can outclass the CPU. When not limited by a poor driver, that is.