I’m not quite sure what this question is asking.
The Cortex-A57 in the Tegra X1 is a different processor architecture than the Cortex-A15 in the Tegra K1.
There are a wide variety of factors for the better performance of the Cortex-A57 over the Cortex-A15. Some of them are system related Here are a few of the reasons, but certainly not all. Processor design and “tricks” take up volumes of books.
First, the Cortex-A57 is 64 bit versus the 32 bit Cortex-A15.
The Cortex-A57 can fetch, decode, and dispatch three instructions per clock cycle, and it executes instructions out of program order to improve throughput. On the other hand, the Cortex-A15 executes 2 instructions per clock cycle with instructions executing in program order.
The memory bandwidth is faster on the Cortex-A57, 25.6GBs vs. 15GBs. The TX1 can use LPDDR4 memory versus the TK1 LPDDR3.
The architecture difference means memory caches are more performant on the TX1.
The Jetson TX1 uses a 20nm process, The Tegra TK1 uses a 28nm.
The list goes on, but the basic take away is that it’s not an apples to apples comparison, and certainly just using clock speeds as a measure of processor speed is a throwback to the old days when people were all using the same Intel processors.
You can look at some benchmarks of the Jetson TX1 vs Jetson TK1 here: http://www.phoronix.com/scan.php?page=article&item=nvidia-jtx1-perf&num=1