The performance between the Exynos 5 Dual and NVIDIA Tegra 3 was rather surprising, but it will really get competitive with the Tegra 4 SoCs. NVIDIA will be utilizing quad-core versions of the Cortex-A15 in some of their forthcoming Tegra SoCs.
The Samsung Exynos 5 Dual can easily handle MP3 encoding with LAME.
Overall the performance out of the Samsung Exynos 5 Dual on the new Chromebook is very attractive. While Ubuntu on the Chromebook isn't perfect (the broken touchpad and sound support, etc), for those looking towards the ARM Cortex-A15 for development purposes or as a test bed for experimenting with Linux on ARM, the Samsung Chromebook is a very attractive bargain priced at $250 USD.
It was surprising to see the wide performance margin the dual-core 1.7GHz A15 had over the quad-core 1.4GHz A9 in the Tegra 3. In a majority of the cases, the Samsung Exynos 5 Dual also easily beat out all of the tested Intel Atom processors. And then there was the Intel Core i3 330M, which was faster, but on the performance-per-Watt this would be a very different story. The Core i3 330M has a 35 Watt TDP while the Exynos 5 Dual operates within a few Watt envelope. Unfortunately due to the varying displays and other hardware differences, an easy power consumption / performance-per-Watt comparison couldn't be done for this article.
Stay tuned for additional ARM Cortex-A15 Linux benchmarks on Phoronix.