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post #717 of (permalink) Old 07-03-2016, 01:24 AM
The Stilt
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Quote:
Originally Posted by Mahigan View Post

Some dude on the bitcoin forums claimed that his motherboard was fried from running 3x RX 480s (under-clocked his cards)....

well...

Take 6x R9 290xs each pulling 66W from the 12v rail and around 9W from the 3.3v rail of their respective motherboard PCIe slot. Do the math...

That is 450W being pulled from the motherboard (I ran that on several machines during the bitcoin heyday and many other users run similar configurations on cheap motherboards).

This user wants us to believe is that 3x RX 480s pulling 80W each from their respective PCIe Slots are somehow responsible for burning out the motherboards 24-pin connector.

Lets do the math.. 3x 80W = 240W.

So let me ask you all... how come many bitcoin miners can run 6 R9 290xs on the same motherboard using PCIe ribbon cables pulling 450W without a single issue yet 3 RX 480s are somehow responsible for burning out a motherboard after pulling 240W?

What is a larger number. 240 or 450???

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.
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