I had the same problem on a new PC build. I figured out that if I changed the resolution from the Windows software instead of the graphics card software and made sure that it was shut down properly by "restart" or "shutdown", the resolution saved. You may have to uncheck the box "Hide modes that this monitor can't display" to set the resolution you wish. Right click on desktop. Got to /properties/settings/advanced/monitor and uncheck "Hide modes that this monitor can't display", click apply then OK, then go back and select your resolution and click apply then Ok again. The setting should save after reboot.