Do not buy TX series from corsair. Im not sure about other series or brands but in my experience the fan ran 100% all the time. I saw many videos and forums about it. After RMAing it and getting a brand new one.. had the same problem. The fan uses a black and red so it cannot be controlled. I took it apart and replaced the fan with one that ran to my fan controller so I could control it.
For the most part many brands get their PSU from the same source. I think corsair gets theirs from seasonic i don't remember.
this is the power consumption with an over clocked sandy bridge-E ( that will use 48 watts more at stock)
all the 660ti are overclocked also and except for one they are under 400 total watts. the max load you want to put on a PSU is 80% of it continuous load for best efficiency. so 400/.8= 500 watts
also lower quality PSUs have weaker 12 volt rails, where you really need to draw power from for the CPU and GPU. a better quality will have 80% of its power on the 12 volt rail or 400 of 500 watts. so a minimum of 34 amps of 12 volts would be necessary; though just the CPU and GPU won't use more than ~300 watts.