i overclocked my mentioned gfx card. GPU Clock is 643 MHz and Memory clock 923 MHz. the temperature at idle is 57 C and on full load is 68C-70C. Can i overclock it to a little bit more. usually how far can i go further. is this temperatures are normal? But when i retart my system the values are setting to default ones. But before restarting everything seems to be normal. please help me. TIA