Ok so I bought a GTX 660 ti and installed it into my machine, which before had been running perfectly on a AsRock Fata1ty P67 Proffessional Motherboard, intel i5 3450 cpu 8gb ram and most importantly a 650watt Corsair tx650 power supply. The graphics card that I had in there was a radeon hd 6670. My problem is that whenever i go to turn the pc on the graphics card displays no signal. Now this is the reason it is not in the graphics card section of the forums is that I actually did RMA the graphics card and it was found to be perfectly functional. See the pc powers up fine and i can here the windows sounds when i log on but i still get no signal to the monitor. My thinking is, and im not proud of it, i bought my psu cheaper second hand from ebay and it makes a rattling noise when turned on. Does anyone think that the power supply (which btw was working with my 6670 which does draw a hell of a lot less power) isnt actually delivering the power under load that it says it should? Im just about to buy a new power supply and as far as i can see this is the only option left. :/ yes. im puzzled to.