Frames rendered ahead which defaults to 3 can cause some input lag for some. The greater the value for frames rendered ahead = better performance. But will increase input lag. Input lag = lag from any input device (mouse, joystick, gamepad, keyboard, wheel etc.). When playing online the best option is setting this to 0 (if you can, if not use 1). By doing so it will decrease frame rates but will decrease input response time. When frames are rendered ahead you are pre-rendering or pre-caching a few scenes from the CPU & driver. Which is place into a internal buffer and is processed by the GPU when it's finishes rendering the previous frame. This way the GPU doesn't stall the CPU. GPU is NOT PRERENDERING anything.
For Radeon users it's called Flip Queue Size. In order to change this feature you will need ATI Tray Tools. Once installed you right click on the ATT icon on the lower left corner of your screen. Go to 3D then to Flip Queue Size and select 0. For Nvidia users it's called maximum pre-rendered frames. In control panel goto "Perfomance & Quality Settings". Click on the "+" and go to "Additional Drect3D settings". Now your able to change the frames to render ahead. You can use the Input Lag Tester to see if you are experiencing input lag. The results of this test should be well below 1.0ms. Try this test at least 2 times (total of 10 tries). You can use your mouse, keyboard, etc. Side note: The longer you hold down the mouse button the higher the input lag will be in this
