The Korean newspaper said that Samsung decided to go with the quad-core Exynos processor as a way to make the tablet more competitive to the new Apple iPad. The A5X processor in the latter tablet has outperformed even the Tegra 3 when it comes to graphics so Samsung is hoping that by bringing in a higher-spec'd chipset, it will be in better shape to compete with Apple's third-gen tablet.
We were able to get our hands on the device during MWC 2012 when Samsung showed it off. You can take a look at the Samsung GALAXY Note 10.1 in action by clicking on the video below. Of course, this video was made with the dual-core Exynos 1.4GHz processor under the hood.
source: IPD MK, PocketDroid via Phandroid