It is a mission impossible to edit a video My laptop is not the fastest one, and I created a blender project. There are a few stretched blocks. I unwrapped them and added a realistic texture.

I want to make a video with the length of 20-30 seconds. This video clip is decorated with a background music. But my problem is that I can't really edit the video, because the audio runs normal but the Video lags (~7fps).

I tried to look the preview only with materials or only with the objects. But nothing helped. I use Blender 2.8 alpha 2 (EEVEE).

In the later render everything is great but its a horror to edit. Any other ideas to show in the preview because even in wireframe mode it lags.
This has been a problem in blender for quite a while. Definately not a 2.8 problem. Not quite the optimal solution but it works is to turn the video into an image sequence and then import it as an image sequence. I usually use ffmpeg to convert the video into an image sequence but I don't know how easy that is from a non unix pc. You can always just import it into blender and export it as an image sequence. I did recently see what I think is a big improvement in the 2.8 video editor where I think this problem is fixed allthough I can't conferm because it crashed 1 second later. 
A different problem which I don't think you are describing here would be just a framerate mismach so make sure your render settings fps is the same as that of your source video. 
(If the fps counter is red the problem is probably the first one I mentioned, could still be both though)