XA2's Snapdragon 630 uses big.LITTLE as well. 4 x 2.2GHz + 4 x 1.8GHz with the 630 vs 6x 1.2GHz + 2x 1.8GHz with the 650. Watching AIDA on various benches on my Xperia X, I rarely ever get the more advanced cores to spin up, so I don't count on them doing a lot.

The lithography and clock speed differences are monumental. At worst, the 630 will be as fast as the 650, but with much less power consumption.

JP1 is a dual core 1.4GHz Krait 300, with really slow (by modern standards) LPDDR2. That's a huge bandwidth and clock/core hit. That's why it's slow.