Orbiter usaly renders the 2D panels 1:1 on your screen.
You can resize them by any factor with the "Panel scale" paramter in the "Parameters" tab. However, orbiter does this not very pretty at all. So unless you need to make the panel bigger it is not adviced (downsizing them makes text very quickly unreadable). Scrolling with the arrow keys is the better choice in 98% of all cases.
The XR class ships address this by giving you the choice between 3 panel resolutions. Check the config file!
The current beta does things very differently and ships that use the new sketchpad should be very pretty at any scale.
Note: If you have an LCD screen, you should always use it at its native resolution! (!!!)