no, they aren't really 8-cores, just 2 CPU's that are 4 cores. This helps with battery savings, but for performance sake it doesn't get you anywhere.
Hell it kind of holds you back as typically BOTH CPU's have a really low max clock speed.
and is that phone the first rip-off of an other chinese phone? Thought I'd never see that before.
Looks like a OnePlus One with a near exact logo of Xiaomi's Mi branding.