Antec 520w and Vapor X R9 280x.. and PSU overestimates

I am thinking about upgrading my 7850 to a 280x, and I started noticing things like.. for example, Sapphire saying that the Vapor X 280x requires a minimum 750w power supply.

I understand that board partners exaggerate the power supply requirements of their cards, but that is a massive difference from my 520w PSU. Even if I consider it as an overestimate, it's still a 230w difference!

1. How much truth is there in these "requirements"?

2. Do I really need to upgrade from an Antec HCG 520w, for a single card solution?

The kind of numbers that get thrown around for PSU requirements just seem insane, and if I was one of these board partners I don't think I could justify publishing such a thing. How many people who don't know better will just go out and spend a ridiculous amount of money on new PSU that they don't need so they can use their new GPU?


By my calculations:

FX4300 - 95w

Vapor X 280x - 230w

7 fans (case fans + HSF) - (approx.)6w x 7 fans - 42w

SSD - 3w

HDD - 8w

Motherboard - 50w (uneducated estimate, as I know little about motherboards power consumption)

TDP - 428w

Using the eXtreme power supply calculator website, it calculated 347w and suggested a 400w PSU. I understand why the manufacturers overestimate the PSU requirement, but sometimes it just seems grossly unreal and I think it's wrong and misleading.

Total system power.

Test System:

  • Motherboard - Asus Rampage IV Extreme X79 LGA 2011 (chipset fan disabled)
  • Processor - Intel Core i7 3960X at stock clock speeds of 3.3GHz with Turbo Mode disabled.
  • RAM - 16GB (2 X 8GB) Corsair Vengeance Pro Series 1866MHz at 9-10-9-27
  • CPU Cooler - Corsair H100i with Quiet Fan Profile
  • Power Supply - Corsair HX1050W
  • Main Storage Drive - Kingston HyperX 240GB SSD over SATA III interface
  • Chassis - Lian Li T60 Test Bench
  • Displays – Dell U2711 Ultra Sharp for 2560 by 1440 and we use the LG IPS 234 & LG IPS 224 with the Dell U2711 Ultra Sharp to run 5760 by 1080.
  • Operating System - Windows 7 Ultimate 64 Bit

you should be fine with the 520W psu as long as its a decent one ☺