Team Fortress 2 Highly Compressed Extra Quality 'link' -

To get "extra quality" performance—meaning high FPS without making the game look like a "Minecraft" mod—you should use optimized configuration files rather than just lowering in-game settings.

Maximizing Performance: The Guide to Team Fortress 2 "Highly Compressed" Extra Quality team fortress 2 highly compressed extra quality

This is widely considered the gold standard for TF2 performance. It optimizes both graphics and networking. team fortress 2 highly compressed extra quality