Pure Motion - Creative Frame Interpolation
CFI is discussed at several points in this review. The HD8600 offers three selections - Low Medium and High. The purpose of CFI is to smooth out motion. This is a feature that started appearing last year on a couple of projectors and is getting more widely used. Many, if not most, LCDTVs now offer it. As with CFI in general, when used with movies at 24fps, the end result tends to have a bit of a "live digital video", or "soap opera" look. As a result, few people use it for movie viewing although it's very popular for sports. The Optoma implementation, however doesn't work with all source types. As a result the CFI will not work on all HDTV sports content.
The Optoma implementation is flawed somewhat from not supporting all content, and for being a little coarse in the Low setting, especially for movies. That said, most projectors don't offer any CFI. Of the closest competiton, the JVC RS25 also offers a CFI, which also is not one of the best implementations around. Use the feature where you like it. Consider it a bonus feature.