incorrect screen resolution

Hello

So I have a MacBook Pro 15' mid 2015 (newest so far) with a bootcamped windows 10 partition.

I have a Fujitsu P22W-5 ECO model connected to my computer with a VGA cabel and a VGA-Thunderbolt converter.

In my settings it says 1680x1050, but that is clearly not the case.

http://www.whatismyscreenresolution.com/ says it is 1120x700, which seems more realistic.

I have no idea what to do, but any help is much appreciated!