On the 4000, processing was needed on TWC's side to make the customized map backgrounds and the radar mosaic from multiple radar sites so you could see everything flow nicely on the screen even if your area was in between those sites. The IS and IS2 definitely have more processing involved than the 4000 as they also add colors for areas where the computer algorithms think it's wintry mix or snow. Raw radar data from NOAA does not show these distinctions, so it's clearly on TWC's end.
