Windows 8 has many features & tweaks but the size of windows border annoying many of us as there is no any option to reduce the windows border size in windows 8. You can reduce windows border size using following simple tips –
Open run command using win+r key now type regedit and press enter to reach registry editor, if asked windows admin password than type your user name & password.
Now browse for HKEY_CURRENT_USER\Control Panel\Desktop\WindowsMetrics
Now double click on PaddedBorderWidth setting to change the value
The default value is -60 , the larger this negative value , larger is the windows border size, change this value to -5 and click ok.
Your border size of windows will be reduced.