AMD FX-4100 Bulldozer
With FFmpeg video encoding the performance was close between the Bulldozer and Sandy Bridge processors, but the input video file is not too big.
When placing more of a video encoding burden on the processor by using x264, the FX-4100 performance was at about the same speed as the i3-2120 while the i5-2400S and i5-2500K were encoding much faster.
The MAFFT molecular biology test also favored Sandy Bridge.