I have an i5-3570K, and one issue that was always present was the fact that if you had a discrete GPU, then you would not be able to use the integrated GPU to use Intel's media acceleration.
My old motherboard had a workaround where it would render games on the GPU, run it through the integrated GPU, and then output from the integrated graphics. But it was hackish and lacked support.
I haven't seen much regarding this specific feature, but new newer chips like Skylake and maybe Kaby Lake allow you to use the integrated GPU processing, even while a discrete GPU is installed?
My old motherboard had a workaround where it would render games on the GPU, run it through the integrated GPU, and then output from the integrated graphics. But it was hackish and lacked support.
I haven't seen much regarding this specific feature, but new newer chips like Skylake and maybe Kaby Lake allow you to use the integrated GPU processing, even while a discrete GPU is installed?