Hello,
You could also Google for either "Reviews or comparative reviews G1.Sniper" and "Overclocking G1 Sniper" (use the exact part number designator for your motherboard in searches). You could also add your cpu to the search string if you wish: "Overclocking i7 2600K and GA-P67A-UD7-B3" to narrow search. The reviews and overclock articles, your searches provide to you, will detailed what RAM sticks were used, the overclocked reached as well as the timings and voltages used. This should provide you with a few proven RAM options to buy.
For your consideration,