The first Note 4 series will have 3GB of ram. Samsung has always pulled updated versions of their flagships out of thin air after the initial release so who knows if they will release one with more. The Benchmarks for both phones are phenomenal and 3GB will be plenty. The major difference between the Exynos and the Snapdragon SoCs is that the Exynos will be 64bit future proof and the Snapdragon won't. That, and the Exynos most likely won't support U.S. LTE bands.