Warning :- Overclocking a video card, even by software supplied by the hardware vendor is likely to render your warranty null & void.

1.Ensure that the card has sufficient cool air flow around it. You can remove your cabinet panels or add an after market heat sink onto the RAM and/or VRM so that it doesn’t get too hot or run very loudly.

2.Get “MSI Afterburner. It can be found here :-

http://event.msi.com/vga/afterburner/download.htm

It provides great control for overclocking and includes adjustments for Core Voltage, Core Clock, Shader Clock, Memory Clock.

3.Download a stress and stability test like “Ozone 3d Benchmark” or AMD Overdrive(for AMD cards only).

4. If you’re running on stock cooler, better leave the core voltage untouched. Increase the core clock in steps of 5 MHz. Keep an ear out for unreasonably loud noises from the card fan. Continuously monitor the GPU temperatures in Afterburner.

5.After each increase, run Ozone 3d stress test for approximately 15 minutes. If the card temperature stays below 90C you’re fine. Fan speed is better left in Auto mode, as manual tweaking can make it run faster, hence louder than required.

6. Repeat previous steps until you get a stable setting with temps < 90C. If you see any artifacts like dots, bezels or random lines while stress testing, lower your clock speed or increase your core voltage in units of 0.01 Volts (only if you’re sure it has abundant scope for cooling).

7. Always adjust one parameter at a time and stress test. The preferable order is Core Clock -> Core Voltage ->Memory Clock. Shader Clocks are only for Nvidia cards and best left untouched if you do only gaming. However tweaking it has complex effects for GPU parallel apps and is better  done after consulting the vendor FAQ.

Thus one easily get 10-15 % extra performance from one’s graphics card without paying extra. Optimum for persons trying to squeeze in a few extra frames per sec in the favorite game. You can also check how to overclock your computer .