Samsung path through the 8 core processor market hasn’t really gone without problems.The company’s Exynos 5 Octa, Exynos 5410 which put in the Samsung Galaxy S4 which made a promise of using four low energy A-7 Cortex Cores along with the powerful Cortex A-15 cores.
But significantly it did not turn out so. For some reason it was found that only four cores were running simultaneously. But when Samsung announced the next generation Exynos Octa, the Exynos 5420, it was earlier assumed that company might have fixed the problem. And this now has been confirmed by the company on youtube through a music video, that now all the eight cores can run simultaneously.
The Exynos 5420 fixed various previous problems and now also the Cache Coherent System is found to fully working, which allows the processor to be used in a HMP mode. HMP stands for Heterogeneous Multi Processing which is a really smart technology as the Linux Kernel ( the one in Android) also needs to learn that all the cores are not at all equal. See the video below.