According to Sammobile, an official S4 has been benchmarked and it's specs are confirmed.
"Somebody with a Galaxy S IV has just performed an Antutu benchmark and revealed all the specifications of the device! It looks like the Galaxy S IV features an Exynos Octa 5410 CPU clocked at 1.8GHz, PowerVR SGX 544MP GPU, 2GB of RAM, 4.99? Full HD (1920×1080) display and a 13 Megapixel Camera. The device also runs Android 4.2 out of the box. The Galaxy S IV retains the menu, back and home buttons, like its predecessors."