It looks like Samsung is developing a new SoC known as the Exynos 5210, which is part of their Exynos 5 Series. Details are unknown but it's thought to feature ARM's big.LITTLE technology in a Quad-Core structure, equipped with Dual Cortex-A15 Cores and Dual Cortex-A7 cores. The Exynos 5210 could also be just a Dual-Core Cortex-A15 SoC.
There is also a high possibility that the Samsung Galaxy S4 Mini could use the Exynos 5210 processor. As the Galaxy S4 features ARM's big.LITTLE technology in an Octa-Core configurations the Galaxy S4 Mini could feature ARM's big.LITTLE technology in a Quad-Core structure.
The device will have a 4.3″ Super AMOLED qHD display with a pixel density of 256ppi and based on TW Nature UX 2.0 running on Android 4.2.2. The Dual-SIM variant (GT-i9192) of the device is rumoured to feature a Dual-Core processor whereas the HSPA+ Variant (GT-I9190) variant is rumoured to feature a Quad-Core processor. The Galaxy S4 mini is expected to be launched during summer in June / July.