I am using CPU-Z to test basic things abot the J7. It reports an Exynos Octa 7580, 8 cores, 8x ARM Cortex-A53 @ 1.5GHz, r0p3, 28 nm.

At all times that I checked, only cores 0-3 are active, and cores 4-7 are stopped. Power saving is disabled.

Is there any way of activating all cores?
Is there any way of at least seeing all of them active, for testing purposes?

I have found a few posts around mentioning that it may be the way the phone+OS kernel keep temperature in check, but I am not sure it applies to J7, and if so, how to circumvent it.

https://forums.oneplus.net/threads/cpu-z-4-core-stopped.435432/

https://forums.oneplus.net/threads/2-cpu-cores-dont-work-at-all.420496/#post-14352587

PS: I find some times that my J7 is sluggish, so I wonder why would it have 4 processors idling if they could work (assuming the causes are processing several apps, which could be tackled by assigning different processors).