When working with raster datasets I often encounter limitations caused by the large size of the files. I thus wrote up a little R function that invokes gdal_translate which would split the raster into parts.

The screenshot to the left shows a raster in QGIS that was split into four parts with the below script.

## get filesnames (assuming the datasets were downloaded already. 
## please see http://thebiobucket.blogspot.co.at/2013/06/use-r-to-bulk-download-digital.html 
## on how to download high-resolution DEMs)
setwd("D:/GIS_DataBase/DEM")
files