Several gaming mouses have options in their driver software to adjust the sensitivity (dpi).
I personally use this one, even though it "only" has 2 extra buttons, it works very well and even has weights so you can adjust how heavy the mouse is.
What I like most about it though is that it saves the macro or hotkey combinations and dpi settings you adjust inside the driver software even if you connect it to a new system. Ever since I configured it I've never had to re-configure it even though I've re-installed my OS several times and even own a new computer now.
But in short, some gaming mouses provide extra settings for it.
Naga can be set up to 5600 DPI, and trust me, it's incredibily fast - read annoying. That new Sensei I think it goes up to double that.
I found it fine with 800 DPI, then set up a tiny higher in games.