CoPSwords

So there is no real danger when your power supply massively exceeds your usage?

So about four months ago I put together my first computer with the help of a buddy. The only thing we salvaged from my six year old computer was a Thermaltake 600w power supply. He assured me that it would be more than enough for my new build. Just the other day though I picked up a Corsair RM750x power supply because I thought the deal was just too good to pass up on. I haven't yet installed the new power supply because I am worried that it might be overkill, and end up being too inefficient to be worth it. Here is my computer: GPU - MSI Gaming X GTX 1070 CPU - i5-6600k CPU Cooler - Coolermaster 212 EVO Motherboard - Gigabyte Z170X Gaming 3 RAM - 4 x 8GB Corsair Vengance SSD - 2 x Samsung 850 EVO 250GB HHD - Western Digital Caviar Green 3TB I used the OuterVision PSU calculator, and it says my recommended PSU wattage is 397w. So I guess I'm just looking for some reassurance/opinions. Should I go ahead and switch to the new PSU? Did I miss anything important? Is the new PSU going to be way inefficient? Any other thoughts, comments, or criticisms would be welcome and appreciated. Thank you in advance.

I was looking at the Polaris 11. The card wouldn't really be for me. I just recently went into debt for a GTX 1070. No, the Polaris 11 would be going into a PC I'm building for a friend's birthday. This would really help me save some cash. As well as provide a better gaming experience for them.