Very jagged edges when imshow an image on a second monitor

Hello,

I am trying to display a 3840x720 RGB image (tiff or PNG) on a secondary monitor of resolution 3840x720 via display port.

I can create the figure, display the image, scale it properly and display full screen on the second monitor.

hfig = figure;
I = imread('image.tif');
set(hfig,     'Numbertitle','off',...
              'Toolbar','none',...
              'MenuBar', 'None',...
              'WindowState','fullscreen',...
              'Position','[1921 361 50 50]',...
              'Color',[0 0 0],...
              'GraphicsSmoothing','off');
imshow(I,'InitialMagnification','fit');
set(gca,'Position',[0 0 1 1],'xtick',[],'ytick',[],'Visible','off');

However, no matter what I try, I get badly jagged edges.

When I display the same image with an image view such as xnview, I get a clean image displayed.

See attached image side by side that shows how "broken" the curved line is on the matlab image (right). There is a bit on the xnview side but that is in the image.

I tried to force and modify some OpenGL settings but no change.

opengl hardware
opengl('OpenGLLineSmoothing',0);

If I make a 2560x1440 image and display on another monitor of that resolution via HDMI, I also get bad image. These two external displays are on the Nvidia M2200 graphics card. I tried to deactivate every possible processing on the adapter but still no luck and xnview works fine.

But using the same matlab code (replacing the position only), I can display the image properly on my main laptop screen (1920x1080 monitor) instead of the secondary monitor. This is on the integrated Intel HD 630 graphics adapter.

Any help would be greatly appreciated in figuring this one out...