New raster engine generate obstructive lines

I send in a support request in which I stated that the images in V8 are of worse quality than the V6 version I have. That might be an unjustified statement.I compared the two versions and the difference I experience seems caused by the new raster engine. I use topographical maps and satellite pictures in my projects and the new engine generates and draws tiny lines over any significant break in colour (and/or) contrast it detects. That is a marvellous capacity, and it might be useful, but if I zoom out (actually at the zoom scale I use to work normally) the original raster is rendered unreadable due to the lines drawn by the new raster engine. What relieves me is that I detect the original raster still available underneath. Is there a setting to disable this feature? I would like to request, at least for as long no such setting is available, to have this disabled by default. It is obstructive in my case and might even affect performance.Gerrit