The dvi24 5 model is DVI-I. The dvi24 1 model is DVI-D. Compatibility is different: The DVI24 5 is compatible with analog and digital signals, while the 24 1 only supports digital signals.
Different versatility: DVI24 5 native support conversion to VGA, without the need for an independent digital-to-analog conversion chip. The dvi24 1 cannot be directly connected to the VGA display and requires an independent digital-to-analog conversion chip.