IMO, you should not use that PSU. From Tom's Tier List: "Built down to a low price. Not exactly the most stable units ever created. Very basic safety circuitry or even thin gauge wiring used. Not for gaming rigs or overclocking systems of any kind. Avoid unless your budget dictates your choice."
Your decision, but a bad choice for a rig with a graphics card.
Everything attached to PSU or fed power by the motherboard depends on clean, stable power. Using a cheap PSU endangers everything attached not just the PSU because one of the reasons they are cheap is that they do not have over/under voltage protection. So when something does go wrong, and that will eventually happen at some point, there is no circuit protection for the rest of your computer.
Another reason cheap PSU's are cheap is that they use cheap components which means that something will go wrong earlier rather than later.