Driver improvements did not increase the tessellation performance of GCN 1.0 and GCN 1.1 to the level of the GCN 1.2 cards.
Memory bus was indeed changed. It got its bandwidth
reduced.
You fail. Incremental changes do mean a different architecture. By your logic, Maxwell and Maxwell 2 are the exact same architecture, but they aren't. Still funny that this oh so old architecture can do concurrent Async compute while nVidia's most modern oh so new architecture can't. Even funnier is that this oh so old architecture is DX12 compatible with FL_12. Newer does not always equal better.
Roti-Kebab :
Please, do you even driver bro? AMD only just stepped up their game with crimson, but we know very well, they are still struggling with drivers in general not just the 380. And yes, i have around 15+ people in my contacts who run a 380 and like 6 of em have driver issues, i'll admit, so does the 960, but not as much, And we all agree nvidia does have much more optimized games out there
This is a long story that doesn't need to be explained here... Short version... Yeah they have issues with drivers under DX11 due to their GPUs having the need for parallel feeding, while DX11 only allows serial feeding. nVidia's GPUs are designed for serial feeding. All this is eliminated under DX12 and Vulkan, which is why AMD cards received the biggest boost, having an R9 290x rivaling a GTX 980 in performance...
And yeah, the reason they have more 'optimized' games out there is because of their dirty GameWorks campaign, which anyone who cares about games should be strongly opposed to.
But enough off-topic talk. We're not helping the thread starter this way.
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Edit towards post below, to not waste more posts on off-topic talk;
http://www.extremetech.com/extreme/213519-asynchronous-shading-amd-nvidia-and-dx12-what-we-know-so-far
tldr;
AMD async = vastly more powerful + pure hardware,
nVidia async = 'light' only + requires CPU resources, aka software solution.