video, graphic detail, & lag fixing questions....

[khortez]

Dunno if i can post this here but, I'd like to know.

Whats video detail and graphic detail in the F3 menu? What are their purposes
and would they be linked to any type of lag that i might have? I'm on a Windows 7 (compaq), and ever since I used it for graal it is a LOT laggier then my XP was. So any answers/help about how to fix lag on W7, and what Video/graphic detail are would be nice. Thanks to those that help.

(Or alternatively, telling me everything on the F3 menu/comp that could possibly make me lag besides lights, weather and particles would be good too.)