Yeah you can't add the two figures together because they were taken at the wall. So the 270w is the full system load with the cpu being stressed 100%. If the application you're using is cpu bound then even a 400w psu would cover it that load. Most server psu's are not 1000w monsters because they don't need to be even with a huge raid array, dual cpus, 64gb ram etc. You'll find the wattage surprisingly small.
I use Cyberlink PD 14 for video editing and that uses gpu processing so even at full whack a 600 / 650w psu is more than fine.
And as for the 700w guy... Not watched the video but unless he had a billion fans / hdds and some very exotic cooling i can't see or understand how a single gpu card plus a processor can get anywhere near that.
My rig is about 6+ years old now and ran i920/930's in it plus 480GTX and 7970 before the Fury. Even the power heavy 480gtx didn't stretch my HX620 psu at the time in heavy gaming.
And to put it into context :
https://www.guru3d.com/articles-pages/amd-radeon-r9-fury-x-review,10.html