Chipgate was so overblown. Besides, there'll probably only be one manufacturer for the A9X because the iPad Pro is the only device that uses it, and it will be produced in much lower volumes than the iPhone 6s and 6s Plus.
There are a lot of variables other than manufacturing process that determines a chip's performance. Could've been something like improper layout that's causing issues. Samsung 14nm process is fine for Exynos 7420 which is currently the best SoC on the market for real world use and not benchmarks.