What you can do is download MSI Afterburner and that will help you to overclock the video card. It's similar to overclocking a cpu where you raise the mhz and if needed the voltage. The voltage is the place you want to be carefull with and only the amount of voltage that you need and in the smallest amounts possible. It doesn't require much but some voltage is needed when the mhz is raised to maintain stability.
cool man well i would study this guide http://www.overclock.net/t/1265110/the-gtx-670-overcloc... Try this tutorial, it goes over EVERYTHING needed for GTX 670 overclocking, and takes into account that each chip is different.A few of my friends followed it and got great results in real-world BF3 games, and synthetic benchmarks like Unigine Heaven.