If you are using and AMD FW13, updating to the latest AMD driver will let you create a custom resolution (such as 1128x752) so you can game at lower resolutions than native
Custom Resolution Utility (CRU) - Page 399
Custom Resolution Utility (CRU) - Page 540
Custom Resolution Utility - Download now!
Simple way to find out what resolutions your monitor supports (Windows users only) | ResetEra
Custom Resolution Utility - Download
Do you know how to cap a monitor refresh rate by 1-2 fewer Hz? - Quora