Phenom keeps up because of the FPU, the x6 especially due to it having six.
The FX-8150 only has four.. they really should have thought it through, yeah rendering is great because of all the integers just it should've, and could've been better.
PIII, for the love of tea.
bulldozer has 8x128bit or 4x256
add the higher clock speed and theoretically you should have more floating point performance.. somewhere along the long, long looong pipe tho it borks up