For me,dual core s3 already faster than tegra 3(tested with my acro s and nexus 7)

It's not bad. Tegra3 a good chip with overhyped 'Tegra' marketing gimmick.
For example, GTA:3 released a THD version, which contained full graphic function and details. Blurs, textures, details etc. In other versions, a lot of these additional graphical options are disabled. However, some phones like Samsung S2 ( what more S3) could handle the full version without a problem. But because it's marketed as a "Tegra exclusive", people tend to believe that only Tegra3 could produce good graphics however in reality it's the full version where else non-Tegra devices is receiving the "lite" version.