5k resolution

Hi! I use last iMac (Retina 5K, 27-inch, 2017) for connect to Windows Server 2012 R2 and I want to increase default screen resolution up to ~5K with same elements sizes as in MacOS. But in my connection I have 2560 x 1440 pixels screen resolution in Windows (on iMac I have 5120 x 2880 pixels). I...