Benchmark result sites are fertile ground for finding info on unannounced phones. The latest discovery is a Samsung GT-I9400, which judging by its model number might be the Galaxy S IV.
The rumored specs of the upcoming Samsung flagship are pretty spectacular - 4.99" 1080p Super AMOLED screen, 13MP camera and Exynos 5450 chipset (quad-core Cortex-A15 CPU, Mali-658 GPU).
The NenaMark 2 result page, however, paints a different picture.
The score shows WVGA screen resolution, 1.2GHz CPU frequency and Mali-400 GPU. Don't be disappointed though, early Galaxy S III benchmarks showed WVGA resolution and lower CPU specs too. Considering that the S IV will likely launch in Q2, this benchmark was probably run on early test hardware with early test ROM.
Of course, these benchmark results can easily be faked too, so in the end they don't give us much, not even a name (how long can Samsung use roman numerals?).