We're still waiting for the first Tizen device – it will launch in August or September according to Samsung VP. In the meantime we get leaks that paint a picture of what the device will be like – a smartphone with 720p screen and an Exynos 4 chipset.
TechTastic looked through the Tizen repository for stuff committed by Samsung and there seems to be support for only two chipsets – the Exynos 4212 and Exynos 4412. The first is a revamped version of what went into the Galaxy S II (under the alias s5pc2xx) and the second is the Galaxy S III chipset.
The chipsets pack two and four Cortex-A9 cores respectively (at 1.4-1.6GHz clockspeed) and a Mali-400 GPU.
This means the Samsung I8805 Redwood, which is the first Tizen to launch according to rumors, won't match Android flagships like the Galaxy S4 in terms of raw power (actual performance is another story, of course). It's the higher-end of the two Tizens that have leaked so far – Redwod and the I8800 Melius.