Summary. You may notice a limitation of 1024 x 768 when setting the screen resolution for a Dell Vostro 420 with the ATI Radeon HD 3450 video card. This may also be a problem for other video cards. It may be necessary to use the ATI CATALYST software to resolve the problem. In the Basic mode, it is possible to choose from a list of available screen resolutions. However, your display may not be able to support these. The ATI CATALYST software is designed to automatically identify the optimal resolution settings for your display and not allow a higher setting than your display is capable of.