In T122238#1550895, @Geez wrote:

Hello Tubleros and thank you for the report.
The Render_W and Render_H do not affect the rendering resolution in game as they are used for different purpose in the cfg file. Has the issue stopped to occur once you have changed the cfg file yourself or does it keep returning? If so, can you try to remove all the cfg and .DayZProfile files and let us know if that has any effect on the issue? As for the option to change rendering resolution in game, the option has been removed from the game due to being obsolete, the rendering resolution is currently being adjusted automatically. Also, if you believe that lower resolution could improve your performance but the resolution is not available in the video settings, you can use the -disable3DRatioCheck, however use the parameter at your own risk as it can result in offset user interface and similar issues.
Regards,
Geez