Funny, I seem to remember several people pointing out the Nitrous engine showing 8.5 FPS under DirectX, and 30 FPS under Mantle (12 FPS DirectX/32 FPS Manlte with Intel I7 4770K CPU), something that Dan Baker of Oxide has said is a 'conservative' estimate on AMD's part. Something that he also said that he was able to accomplish by himself in two months.
Lessee... 30 divided by 8.5 equals... 3.529, or about 3.5x the framerate That's a little bigger than thousandths...
Been posted before, but here are the numbers again. See images 13-14 here. Dan Baker of Oxide's comments track quite nicely with these numbers, and the fps count on the video I linked above seems to track with these numbers as well (actually, the FPS numbers in the interview footage linked above are usually much higher than 30fps)
http://imgur.com/a/Oqmuf#12
Nixxes' Katzman (the Thief guy) revealed during APU '13 that “very early figures from
Thief” (which is “not fully running on Mantle yet” showed a big reduction in draw call overhead. “Before, we would often see about 40% of the CPU time stuck in the driver, in D3D, or in various threads,” he said. “The early measurements we did, right now we have that down to about a fifth of that.”
So, according to THAT developer, he saw an approximate 80% reduction in CPU time used for drivers, D3D, and various threads, even though it wasn't fully utilizing Mantle yet. That was about two months ago...
I haven't seen ANYTHING that shows a mere thousands of a percent increase with Mantle. Perhaps you'd like to share your sources with the class?
If you don't have verifiable hard numbers of your own to share, you are of course welcome to wait for the Star Swarm Steam release (this month), the BF4 Mantle patch, and Thief (Feb 25th-ish), along with the rest of us.
In the meantime, when THREE game engine developers continue to tell us that they are seeing huge gains with Mantle, well they are putting their own reputations on the line by doing so, and NONE of them work for AMD so I tend to take their thoughts and comments on the subject a little more seriously than AMD's own comments. After all, the game developers are the ones that get to make the stuff work, AMD just provides the framework.