Quote: "Its the opposite for me, My viewports quality is poo, no matter what i do. then my renders perfect."
Thats meant to happen for performance options, if your view-port was 100% perfect it would lag like hell since it'll be rendering so many frames in real-time to get a excellent and amazing results.
The view-port is there for designing your work, the renderer is there to perfect its final product for show.
But you can improve the view-port but it could have a bad result on your GPU/CPU causing it to go over your usual usage limit(lets say over the limit that CS:S would create).
You could use a real-time shader; for
example.
However if you just want to improve your textures in the view-port, then go to Customize > Preferences > Viewport> Configure driver, then set it to 1024, 512, and also Linear on the last two.
This can improve the texture and howl view in the view-port, and it really doesn't take much processing power then before.