A bit slower with CPU rendering is an understatement. LOL. I'd say the difference between Firefly and Superfly is about 10 fold longer, if not more, depending on quality settings. [Edit: Superfly seems to choke on transparencies, and I use a lot of them in my scenes as well. ] Until I have an Nvidia card -- if ever, given the price difference -- I'll only use Superfly in those tricky situations where Firefly doesn't really work well (IDL, diffuse light, and white walls, for example). So it won't be my go-to renderer, but it will be of superb usefulness for those renders where Firefly has me throwing up my hands in despair.

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PoserPro 2014, PS CS5.5 Ext, Nikon D300. Win 8, i7-4770 @ 3.4 GHz, AMD Radeon 8570, 12 GB RAM.