Originally Posted by The Stilt
Hawaii or Fiji based cards don't draw anywhere near the maximum allowed by the specification (i.e 66W) from the PCI-E slot. They draw the power for the GPU VRM from the PCI-E power connectors and the power drawn from the PCI-E bus itself only feeds VDDCI VRM and the display interfaces (on Hawaii) and MVDDC and display interfaces on Fiji.
Oh really now... then how does a MSI R9 390x Gaming 8g card get to pull an average of 344W then? Remember.. the card has a 8 pin and a 6 pin connector. That means 150W and 75W for 225W.
For this test, we measure the power consumption of only the graphics card via the PCI-Express power connector(s) and PCI-Express bus slot. A Keithley Integra 2700 digital multimeter with 6.5-digit resolution is used for all measurements. Again, the values here only reflect the card's power consumption as measured at its DC inputs, not that of the whole system.
Are you going to tell me that it is over PCIe power connector spec?
Therefore I have to ask... where did you get your information from?