I have a raster : population density of Ivory Coast. I need to convert it to points, but I met several problems because of the size I think.

Here is what I tried : 

1) GRASS GIS 7 command : r.to.vect => It works but takes several hours !

2) SAGA (2.1.2) : Raster values to points => It doesn't work (Couldn't load gdal_MrSID.dll -> but gdal_MrSID.dll is well installed in the SAGA package).

3) GDAL/ORG -> GDAL Conversion -> gdal2xyz -> It works but takes a lot of time (after 15min Processing algorithm still on 0%).

4) Raster -> Conversion -> Translate -> Save as ASCII grided XYZ. Then Layer -> Add Layer -> Add Delimited Text Layer : 

         File name : the created file : xyz file
         File format : Custom delimiters : Tab & Space
         Record option : Unchecked the "First record has field names"
         Geometry definition : Point coordinates : X field = field_1 ; Y field = field_2.

   Layer appears in the Layers Panel (contains 40 millions points), but the map is empty ! 

Does anyone have a solution?