Is the disc scratched or seems to be dirty on the surface? If you are applying compression, it might take more time if it’s set to higher compression, than if the source disc already fits on a single layer disc. How “strong” computer do you have (CPU)?
Another issue could be that the reader is not in DMA mode. In the settings there is a button you can press to force the reader back into DMA mode.
Fengtao offers a 30 days full trial period so I don’t understand why you haven’t noticed this before you bought it.