The maximum DVI-D input is 1280x1024 @ 60Hz (pixel clock of 108MHz). If you feed a higher resolution into the unit, it will not display the image correctly. Please note that What is EDID? will normally 'tell' the computer what the maximum resolution of the scaler is, so it's best not to try and force an output higher than the receiver can cope with.
If you feed an analog input into the connector (DVI-A) then the unit will
sub-sample it and work fine - but with a loss of resolution.
See DVI-I DVI-A and DVI-D.