Comment on Mantle Boost
You ought to take a lesson in logical reasoning.
Mantle mostly helps in "CPU bound" situation does lead to a conclusion that "it’s actually for boosting low-end CPUs."
CPU-bound vs. GPU-bound is a relative comparison of a GPU and a CPU. While low-end CPU is the result of a comparison between CPUs. One measure (CPU/GPU) simply cannot lead to another (CPU/CPU).
You could have a PC with the highest end CPU currently available, but still being CPU-bound due to the GPU being even more powerful. In such a case, Mantle will offer big gains. Similarly, you could have a low-end Celeron paired with a even lower GPU, and Mantle will help a bit but not much.