I havent done any overclocking myself but the card came from the manafacture with a slight overclock (its a BFG card). I didnt know i could check the temp of my graphics card but i will check it out now. When playing HL2 my CPU temp is about 44 and the motherboard is less than that (about 35 or something).
edit: I cant find a temp reading for my card. I went do display properties and then advance and the nvidia forceware thing came up but theres no temp reading on any of the screens