I think the default setting is to dither down to 16 bit, based on the assumption that the audio card will be 16 bit. I \"unchecked\" the \"dither to 16 bit\" box and chose 24 bit as my audio card capability, since I run all audio at 24 bit until premastering is completed.
Actually it does indeed dither 24 bit files that are imported into the instrument editor. It dithers them as it creates the gig file so once the instrument is saved, it is a standard 16 bit instrument and acts identical to any 16 sampled instrument. The GigaStudio does however mix and do the pitch stretching and dsp work on those 16 bit samples in 32 bit and then it can play, depending on the audio card, the audio at 16,24 or 32 bit. There is definitely a benifit to playing back at higher bits and no cost in performances as far as I know. I think 3.0 will probably offer true 24 bit playback when it comes out wich will be real cool.