The first round of Tizen devices will likely run on Exynos 4 chips
We're still a few months away from seeing the first Tizen phones hitting the open market, but we're seeing some indications of the kind of processors that may be used in the first round of handsets. Given that Tizen is a joint venture between Samsung and Intel, you would assume that one or both of those companies would be supplying the chipsets for the devices, and we're seeing evidence it will be Samsung.
Apparently, Samsung has been submitting code to the Tizen repository that explicitly reference the Exynos 4 Quad (4412), and there have also been lines that reference 4×12, which could point to support for the Exynos 4 Dual (4212) as well. Going on a timeline of right now, this sounds like good news, but keep in mind that the Exynos 5 series chips are already on the market.
So, if Tizen devices are launching with Exynos 4 in Q3 as expected, that would definitely put Tizen devices on a lower tier, although the chips would still offer very good performance.