An Ultrabook Day
Normally I plant myself into a seat facing a mid-range PC. Today I am in front of a Ultra-mobile PC experience typing from my lap. My mission was to see what I could gain from an integrated graphics chip, and the best way was to use one to do the testing and tweaking.
I began and ended my work chopping up the shaders until they started to return performance. The bottom line is that I went from 18 fps to 40 fps by reducing the complexity of the shader, and when I switched off some of the features I got upwards of 70 fps with a terrain and some characters running about.
It is fair to say my shader slicing removed some things you might have wanted to keep such as multiple textures, normals, shadows and other small effects but the experiment was to see 'WHO' was spending the frame rate.
It was clear that on an integrated (and I suspect low end card), that the shader is real bottleneck here and it's a case of figuring out which things I can keep and which things I cannot have to get the performance and visuals that pleases. I dare say some pre-baked processing and hacking would be required to get the visuals on lower end systems, but it's a great start to see the performance hit 90 fps in some cases on what is essentially a fan-less graphics chip!
I still have some reductions to chase through quads, reduced terrain polygons and some more occlusion tricks but it is clear to me now that it's the shaders themselves which slow down the non-mid range graphics solutions. From this info I can add a few extra settings to the slider system to allow these ideas to be tried on the variety of low end systems out there.