Especially in professional settings where that extra minute or so, added up over multiple projects/renders and team members, can mean the difference of thousands or even tens of thousands of dollars, if not more. Looking at things in terms of percentages is useful but absolute values are important, as well.
The people do love them a good ol’ fashioned -gate.
I think it’s the latter. AMD’s spent years trying to make their GPU serve their CPU. It was apparently one of their big incentives for buying ATI in the first place, as illustrated by the AMD Fusion effort that gave us those weird modules that had two integer units with a FP unit. They were never able to make it work particularly well, but since then they seem stuck and incapable of getting actual performance from their GPUs that’s in line with theoretical performance.
That’s twice as much AMD as other brands! /s