I have been considering getting another 670 (sli) to add to my pc. I have a couple questions concerning if my psu unit will be sufficient HX650. I have already used extreme.outervision.com/psucalculatorlite as a reference to how much power draw my pc will use which is around 480w. I’m more worried about the amps that my power supply has which are 52 if I believe. I have read that for sli 670s you should have in the 60 range for amps on your power supply unit. I was just curious on your thoughts on this issue. (I am aware of guru3ds review also.)
It will work. I know GTX 560 Ti's were SLIed on HX 620 (old one), and GTX 670 uses less power. Even while adding maximum power consumption, there's no way you'll hit the limit. Don't forget HX series PSUs are one of the best power supply units in the world.
Don't forget he has an Ivy Bridge CPU, which has lower TDP, and it's non-K one, so there's no overclocking. I'd estimate him hovering around 550 watts.
A rasa kit is a water cooling kit. Also, I do agree he is doing quite a bit of overclocking with this CPU there. He will have more power draw from his CPU and the fact he is using a water cooling system would draw more then your standard fan. You will be fine with a single 670 if you start to overclock it can change how much power your computer is drawing and in the even you were to add a 2nd 670 you would possibly want something larger then 650 however most get a single card and stick with it till the next large update gpu wise comes out and with the current trend of graphic card power consumption its on the downturn rather then the up.
Your HX650 is a highly efficient power supply with enough power for your 670 sli setup. However crazy 4.8ghz overclocking would change that