It’s a 3D render of the SoC rather than a photo of a production unit. In the same tweet, Samsung is talking up the energy efficiency of the chipset.
Up close with the #Exynos 5 Octa mobile processor #GreenTechnology (pic) twitter.com/SamsungExynos/…In case you missed it, the Exynos 5 Octa uses ARM’s big.LITTLE design. It has two groups of four processor cores – the big group consists of four blazing fast Cortex-A15 CPUs, while the LITTLE group has four power-efficient Cortex-A7 cores. That’s eight-cores in total, hence Octa. Only one of the groups is active at a time, the other goes to sleep (similar to how NVIDIA's Tegra 3 chipset works, but with more low-power cores).
— SamsungExynos (@SamsungExynos) January 24, 2013
Samsung claims a 3.3x reduction in power usage thanks to the A7 cores, which are enough to handle menial tasks and are only 13% of the size of an A15 core, so they’re cheap. The overall performance is reportedly the same as an A15-only design. The switch between core groups happens in 30-50ms.
You can read more tech details on the Samsung Exynos 5 Octa chipset over here and get even techier details in this PDF.