There are two means through which Nvidia Dynamic Super Resolution can be enabled for a game or games.
Most users will first become familiar with DSR through the GeForce Experience application. Within the app. users can optimise their settings and, if the game is compatible with higher than normal resolutions and/or UI scaling, select a DSR resolution. The optimisation process may automatically set a DSR resolution for you if appropriate, but clicking on the tool icon will allow you to manually selected one if at all possible. The graphics card will automatically downscale the frames sent to the monitor to that monitor's native resolution.
Users searching for a DSR sweet-spot, or enable it in games incompatible with GeForce Experience, can instead unlock these super-sampling resolutions in the Nvidia control panel. From here you can select a scaling factor at which a scene will be rendered and from which will be downscale to the monitors native resolution. Note that for a 1080p monitor 1440p has a scaling factor of ~1.7, whilst 4K is can be unlocked with a scaling factor of 4; if your panel's resolution is different from 1080p you'll have to compensate accordingly.
The Nvidia Control Panel includes a "DSR Smoothness" variable, which subtly adjusts the Gaussian filter used when downscaling the image. This setting, similar to settings on enthusiast tools such as SweetFX, subtly sharpens or blurs the visible image and is really a matter of personal preference. Play around with this setting to find yours.
Once the DSR resolution settings are unlocked they'll appear in the in-game graphics options. Applying them through GeForce Experience will set them to default on launch, whereas you will want to manually set them if you unlocked the option via the Control Panel.
Currently 1440p is a resolution that generally results in good frame rates, and is used on a variety of high-end professional and gaming monitors. Although picking up in popularity, 4K is still relatively rare and more well suited to multiple-GPU configurations except where a game is particularly forgiving. Through liberal use of DSR on your Nvidia-equipped PC you'll be able to determine if your system is capable of driving a higher resolution panel when playing your favorite game, before you buy the new monitor. Nifty.
Nvidia's implementation of DSR is appreciably slicker than AMD's VSR, and is a little bit better sign-posted. As with VSR and other super-sampling techniques screenshots taken will be at the super-sampled, rather than native resolution. Direct image quality comparison is therefore difficult without dedicated capture equipment or utilising the same Gaussian filter the renderer uses to downsample.
