I'm new to QGIS, and haven't used arcGIS in about 5 years, however I've just seen someone using arcGIS and was able to quickly switch between overlapping rasters when checking registration. The top half of the screen was one raster, and the bottom was another, and the mouse was used to move up and down in real time switching between the two (I'm probably not explaining this very well).
The images I'm working with are very large (2x1GB geotiffs) and of the same area. There is a good 5second lag between switching layers which makes it difficult to see if there is good alignment.
Does this functionality exist in QGIS, to quickly switch rasters in real time?