RE: Upgrade Alienware X51 power supply
That's weird that you state that the 330 watt doesn't support the NVIDIA® GeForce® GTX 760 Ti with 2GB GDDR5.
When I go to customize a new Alienware X51 I select everything I have with the one I currently have and when I select the NVIDIA® GeForce® GTX 760 Ti with 2GB GDDR5 and view the order I see that the power supply that will be shipped is a 330 watt. So why are you saying that the 330 watt will not worked. I have even called into Dell support and was told that a 760 would be compatible with the 330 watt.