DPI makes a huge difference. This is coming from a non-believer of gaming mice and keyboards. I went from a wireless Microsoft optical mouse to a Logitech G5, and I can never, ever go back to that. Depending the game your playing. I use around 1000 DPI normally, and around 1500 while playing. Shoot for something around 2000. Razer makes a 4000 DPI mouse. But, I personally think that's a bit too much.