nope, increasing mouse resolution (dpi) allows the mouse to track faster while keeping the same precision. there is actually less precision from the users point of view since small hand movements = bigger on screen movement.
thats something to think about if you think buying a 2000 dpi mouse will give you more accuracy than a 400 dpi mouse.
Actually, a good 2000 dpi mouse will have an adjustment for dpi, and as my G7 does, its two buttons on the mouse, that can change regarless if you're in a game or not.
Not only that , but this mouse is extremely accurate, I can nearly draw freehand in many paint programs with it, and comes in real handy using Adobe Pagemaker (among other things).
I had reservations spending $75 usd on a 'gaming' mouse, but I'll tell you, I've never been happier. The only real problem I have with it, is that sometimes, if you do not make sure the batteries are put into the charger correctly, they dont charge, but it is something that I personally can live with.
That being said, I'm sure there are a few other mice out there that are as good as my G7, and maybe one or two that are better, but I would buy this mouse again, because I know well it works, and I am used to it.