Samsung Exynos 5420 and will feature a higher clock speed along with improved optimization for the 8 integrated cores. Not technically a true octa-core chip, the Exynos 5 Octa is comprised of two sets of quad-cores with one set of Cortex-A15 chips doing the heavy lifting while the other set of quad-core Cortex-A7 chips takes care of the light housekeeping. Not all 8 cores can be used at once. When one set of quad-core chips are being used, the other cannot.
Recently, a road map from low cost chip producer MediaTek showed off a true octa-core chip coming, manufactured using TSMC's 28nm process. Mass production of this chip, the MT6592, is expected to start in November with the first handsets powered by the silicon to launch early next year. All 8 cores will be available for use at once.
Turning back to the tweet about the Samsung Exynos 5 Octa, the Korean tech titan said that it will be holding a Twitter based contest based on the evolved chip and the rules will be released next week. According to Samsung, the prizes will consist of Exynos powered devices.
source: @SamsungExynos via SamMobile, SammyHub