Hello @uav, and welcome.
It’s hard to say without more detail. Regardless of the window size, a lot depends on what you are trying to display within that window. The map will only render those features that are within the current map extent, and you can also control the minimum zoom level that features are displayed, so that if you’re zoomed out to full extent, it’s not trying to draw all features of all layers.
Consider the MinVisibleScale of the features, and the MinVisibleScale of the labels.
Please provide more detail regarding the map layers and features, and perhaps your drawing code, if you still need more direction.
Regards,
Jerry.