Just to give you an example of how bad that PSU calculator is, here's what it says for my sig rig:
That's with "1 hour per day" selected. Here's with "Always On (24/7)" selected:
But, the highest power consumption I have ever seen according to my Kill A Watt is about 361W (I saw 425W, so with exactly 85% efficiency that's 361.25W) - and that was very difficult to achieve. I had to really put some major effort into getting it up that high. That means my power consumption will never exceed 360W.
Now, according to MSI Afterburner, my GTX 780's overvoltage is +38mV. I don't know what that equates to as an Overvoltage percentage, but this so-called "PSU calculator" is already extremely inaccurate and so it would be a waste of my time to try and figure it out.
So yeah, that PSU calculator isn't a calculator at all. At best, it's an estimator, and it's a horrible one! Don't trust it. Again, as you can see, at minimum, it's 263W above my actual. At maximum, it's 301W above my actual. Or, if we go by the recommended PSU wattage, then it ranges from being 313W above my actual all the way to a whopping 351W above my actual.
Unfortunately, there is no PSU calculator in existence that is accurate.
Edit: For fun, I decided to see what it would say if I chose 50% CPU utilization with just 1 hour per day usage:
This thing is HORRIBLY inaccurate!
Here's another "calculation" with my GTX 780 at stock (full reference stock according to this "calculator"), 50% CPU utilization, and 1 hour per day usage:
What the freakin' hell? THERE'S NOTHING I CAN DO TO MAKE IT EVEN REMOTELY ACCURATE! Good lord!
Edited by TwoCables - 8/26/16 at 11:58pm