If you're finding your frame rate decreases after playing for a certain amount of time, we recommend enabling texture streaming in the 'Settings.xml' file.
To access the Settings file, follow these steps:
1) Locate your Steam Settings folder (default should be: C:\Program Files (x86)\Steam\steamapps\common\No Man's Sky\Binaries\SETTINGS)
2) Open the file called TKGRAPHICSSETTINGS
3) Find the following line in the file: <Property name="TextureStreaming" value="Off" />
4) Change 'value="Off" to 'value="on"
5) Save the file, and close it
If this doesn't help, you can also try:
1) Lower your Anti Aliasing settings in the Graphics menu
If you continue to experience issues despite the changes above, please submit a bug report and we'll do our best to review the issue.