Try using another cable and/ or another port. You may have a damaged/ mulfunctioning port on your gpu adapter or on your monitor.
Make sure that the windows power plan is set to "high" and that the screen does not use any power save mode in windows or in it's own menu options.
Don't use any screensaver or pc hibernation mode either. (all the above is just a precaution)
Or it may just be a bad card, or a card with unstable voltages and clocks, so try experimenting with msi afterburner a bit.
Make sure to also clean install the latest drivers (15.7.1 or 15.11 beta).