When Apple released the iPhone 5 it didn’t contain a quad-core CPU as many people had expected, however Apple did claim that the new phone was up to twice as fast as its predecessor. The most likely reason that Apple could make such a claim is that its A6 CPU uses the Cortex-A15 architecture. With the recent release of Google’s new Chromebook, which is powered by Samsung’s Cortex-A15 based Exynos 5 Dual (Exynos 5250), the benchmarking gurus have now had a chance to really test the new architecture from ARM and the results are amazing.
The Exynos 5 Dual is a dual-core 1.7 Ghz Cortex-A15 CPU that boasts a 12.8 GB/s memory bandwidth. We already know that it is faster than Apple’s A6 but more recent tests run on the Chromebook using the Phoronix Test Suite show that the CPU is faster than Nvidia’s quad-core Tegra 3 and at least two different Intel Atom models (the N270 and the Z530).
Since the Chromebook can be made to run Ubuntu, it means the Linux-based Phoronix tests can be executed on the same OS and attempt to use a level playing field. This means the results should be more accurate when compared to more subjective browser based tests like the Sunspider benchmark.
In the tests the Exynos 5 Dual was pitted against the quad-core Tegra 3 running at 1.4Ghz, the single-core Intel Atom N270 running at 1.6Ghz along with its cousin the Z530. These first three CPUs didn’t pose any real threat to the Exynos 5250. However some more worthy opponents were also thrown into the ring: the dual-core Intel Atom D525 running at 1.8Ghz and the 2.13Ghz Core i3-330M.
So how well did the Exynos 5250 perform? The test suite includes many different types of real-world and computational benchmark tests and in general the Exynos 5250 is upto twice as fast as the Tegra-3 and three times as fast as the two single-core Intel Atom chips. It is also roughly on par with the dual-core Intel Atom D525. However when compared to the i3 CPU the Exynos 5250 has a long way to go, but that isn’t surprising since the i3 is running at over 2GHz and, although called a mobile processor, it isn’t really suitable for the same applications as the ARM based chips.
Taking the real-world H.264 video encoding test as an example, the Exynos 5250 manages 10.62 frames per second, the Tegra-3 8.13 fps, the N270 and Z520 can do 5.08 and 4.93 fps respectively while the D525 marginally beats the Exynos 5 Dual with 11.61 fps. The i3 easily beats the rest with 38.84 fps.
For pure computational tests the Exynos 5250 is beaten only by the i3. Under the Monte Carol flops (floating-point operations per second) test, the Exynos 5250 managed 167.9 Mflops, the Intel chips (N270, Z530, D525) managed 47.98, 48.2 and 65.15 Mflops and the i3 stole the show with 260.62 Mflops.
Since the Exynos 5 Dual is starting to enter into more mainstream devices, like the Nexus 10, it looks like the Exynos 5250 is the processor to beat.