i wouldnt overvolt that card with the reference cooler on it, leave the stock voltage and slowly increase the gpu clock offset. make sure you are always monitoring your temps when gaming. overclocking is a slow and sometimes frusterating process. it can take a while, because sometimes crashes don t occur for half an hour or more. what is the stock boost clock on your card? not what it says on the box, the actual max boost speed you are hitting?