Are you finding it ok to move about in within the editor?
If yes, detach the preview window and make it full screen, then see if your framerate drops then.
I found that although my computer could handle the editor window when it’s smaller, it was ok, but then when I tried to launch my game (in full screen) my pc wanted to die.
The way I got around this was adding a quick blueprint to take the quality of the some other settings down (Just like in a game where you turn down the graphic settings).