To ensure you are getting the best performance out of your graphics card, you can download and install latest drivers (based on manufacturer) here:

Force the System To Recognize Primary GPU.If you meet the game’s requirements and are not running any additional programs, you can try the following troubleshooting steps: If you are experiencing crashes when trying to play The Elder Scrolls V: Skyrim Special Edition, you should first check to ensure that your machine meets the game’s minimum requirements here and that you are not running any additional programs in the background. Instructions for how to remove a mod can be found here: How do I uninstall a mod for The Elder Scrolls V: Skyrim Special Edition? You can also see what Mods you have subscribed to and unsubscribe from them here. You can then add them back to your game later. This can cause unforeseen issues, for example, black screens, crashes, and visual UI errors. To eliminate these as the cause, you will need to completely remove mods from your game.

Note: If the game has been recently updated, mods and addons may not work properly until they are updated by the Mod creator.

Skyrim steam error 15