regs, 17 Jul 20155-core? second digit in exynos nomenclature means number of cores.7420 has 8 cores (working at the same time).
Btw this one (7580) is 8xA53 @ 1.5ghz.
The naming scheme used by Samsung these days seems random.
Also J5 and J7 launched with super amoled display in India instead of TFT screen in Chinese market.