Inspiron 3847 - Graphics card and power supply

Hi! I have a Dell PC in which I used to have a GTX 760. I replaced it with a 1070; the card works fine, but my PC now takes longer to boot (double POST). I already have an EVGA 650 G2 power supply and I thought it would be fine for the 1070, but something (?) needs 150W or more on the 3.3v/5v rails and is only getting 120W. Apparently, changing my G2 PSU for a B1 would solve the issue, but I'm not sure about the quality of B1 PSUs. Also, I could return the GTX 1070 and get a 1060, which would work with my current PSU, but then I'd lose some performance. So I'm wondering what I should do at this point and would appreciate any input!

Here is where I got the clues about the PSU.