Mine estimated the same power draw (+/- 15W) and it stilled browned out. Like I said, it might have just been a bad PSU on my end (it was an EVGA gold 650W, so they are pretty reliable). Its just something to keep in mind, I dont have any water-cooling and I have 2 140mm fans up front, 120mm fan rear exhaust, and 140mm top exhaust, plus my CPU cooler (Cryorig H5 Ultimate). So nothing out of the ordinary for my fans. If you go with a 650W, you also wont have much wiggle room if you want to upgrade. Just something to keep in mind and save you from having to replace the PSU like me. Whatever you do, dont get anything lower than 650W, I can almost guarantee you will have power issues. PC Part picker is good for a benchmark Wattage to give you an idea, but once you get under -load, it can draw quite a bit more. Vega 64s are really bad for that.