If you want to monitor your CPU to GPU ratio, and Frames Per Second in game.
there is a nice overlay built into BF3
Hit the [`] key and open the console
then type the following, and press enter after each line
FPS type – “Render.drawFPS 1” without the “‘s
this will show current frames per second, 60+ is ideal if using vertial sync it will match your monitors refresh rate, 60HZ monitor = 60FPS, 120HZ = 120FPS if you are dropping below then lower your settings for better gameplay.
CPU/GPU type – Render.PerfOverlayVisible 1 without the “‘s
this will display a performance graph – Yellow is CPU, Green is GPU (graphics)
If the CPU/YELLOW is below the GPU/GREEN then the CPU is bottlenecking the graphics cards.
found it by googleing benchmark tool BF3, I wanted to get my settings perfect.