Well, as you can read here, the quality isn't really there. It's pretty much the lowest you can have. It will deliver 500 watts, but at an efficiency of 70%, which is not very great for your power bill. Also, you've got a fairly high end video card. You realise that it is your PSU that deliver the power to your GPU ? If under high load it can't keep a stable voltage, performances will drop.
But for 40$, you can't really get better, or worse.