Sammobile managed to get their hands on the Samsung Galaxy S4 that actually features Samsung's own Exynos 5 Octa chipset rather than the Qualcomm Snapdragon 600 that will be available in most regions. Judging by the results, it looks like Samsung's high hopes for the Exynos 5 Octa were well founded.
Unfortunately, Sammobile.com is still working on a full review of the GT-I9500 Samsung Galaxy S4 but in Antutu and Quadrant benchmarks, Exynos 5 Octa Galaxy S4 was faster than any other device, including HTC One and Sony Xperia Z. It scored 27417 in Anutut benchmark and 12726 in Quadrant benchmark.
According to the screenshot from Antutu, the four Cortex-A15 cores were apparently clocked at 1.8GHz which is a good 200MHz higher than what was originally announced by Samsung. In case you missed it, Samsung only noted that the Exynos 5 Octa in the Galaxy S4 should be clocked at 1.6GHz and according to details the four Cortex-A7 cores are at 1.6GHz and 1.2GHz is for those four Cortex-A15 ones.
The bigest mystery is still the battery life that should, at least according to all previous rumors, be quite better than on the one based on Qualcomm's Snapdragon 600 chipset.