Oh hey, i can answer this as I have done this in Tribes.
Lower dpi = mouse moves slower across the monitor and higher dpi = faster mouse movement. it will zip across if you set it high enough.
it is dots per inch or something along those lines, and it basically means the same hand movement you make will cause the cursor to move a little or a lot depending on your dpi. my g500 allows me to change it to customizable settings at the push of a button so i can have a speed i use outside gaming and a speed better suited for games. Like in Tribes, I liked it to be lower than normal for better aiming.
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There is no shame in not knowing; the shame lies in not finding out
Ok, so the only thing that I don't like about this mouse so far is that the cord isn't retractable like my last mouse. Other than that, I'm quite liking it, I really like the forward and back functionality on the thumb buttons.
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Meat is murder. Tasty, tasty murder. http://img.imgcake.com/drakeryn/raydynjpgam.jpg