With secondary monitor plugged in, yes, perfectly normal. to test if card is faulty, do not use OC tools or increase voltage, simply set the GPU clock to 850 MHz, and try there. IF it still fails, then try 800 MHz. If it does not fail @ 850 MHz, to 800 MHz, then the card is for sure faulty, and needs RMA. IF it crashes, I'd still RMA. There is NO reason to use voltage adjustments to get stability. My cards work perfectly fine, so should yours.