Goo phone MTK6582 I6 Plus - Very slow, Do I need To Root?

Hello my friends, I made a purchase on Dhgate.com a Goophone i6 Plus, the seller said the device was MTK6582 Quad Core and RAM of 1GB. Now he arrived, he found it very slow and downloaded CPU-Z to check, I came across this, MT6572 4 cores and 512MB RAM (Screenshots). I do not quite understand processor, as do, to enable the two nuclei that are "stopped"? As for RAM, the device is consuming almost it all, which is causing crashes on, is there any solution? Help me please, I spent a lot from this unit.
If you have to do root, I do, no problem, except that I can not activate the USB debug option because it use Apple's Settings application.

Screenshots in the comment below.