Alright, so it's stock which isn't a bad thing.
The best way to test it is using a single player game. I personally use COD4 because it's easy to ALT-Tab out of the game.
Anywho, always leave the core and shader clocks linked, and increase the core and memory clocks up 5mhz, and test it out in the game, by playing 5-15 minutes or so. Then, minimize the game (if the overclock seems successful, which means no strange artifacts or game crashing) and increase it by another 5mhz, and repeat until you find the sweet spot.
If you get the "Nvidia display driver has stopped working and has recovered" message, don't be worried, because it's happened to me alot from giving the card too much overclocking.
Just be careful!