The Mac Pro 4,1 & 5,1 have plenty of PCIe AUX power, unless you need more than 300 watts for your GPU(s). Remember you get 75 watts from the PCIe slot. Each PCIe AUX 6 pin connector in the Mac Pro towers delivers 150 watts. Yes all three power pins in both of the PCIe AUX plugs are connected. The PCIe specifications don't required pin number two to have power, but it also does not prohibit it either. In the MAC Pro 4,1 / 5,1 it is connected. To be clear, this delivers the same power as a 8 pin connector without the extra sense and grounding pin on the 8 pin plug. Just buy the correct 6 to 8 Pin PCIe AUX cables and you are all set. I'm running a NVIDIA STRIX 980 Ti OC with two 8 pin plugs (150w + 150w + 75w = 375w). The Mac Pro 900+ watt power supply can handle it. I also have two 130 watt x5690s. No issues during stress testing. Need more power... Cut the plug off the apple power supply and terminate it with the standard ATX connectors.. Then you can run additional power from a new replacement power supply of your choice.
Make an intelligent choice. If you use something more, it should wear out sooner. Some of these machines are 7 years old and taxing a 7 year old power supply can cause it to reset or become inoperative.
Here is some great information about computer power and how much you can use.
http://www.overclock.net/a/gpu-and-cpu-power-connections
Make an intelligent choice. If you use something more, it should wear out sooner. Some of these machines are 7 years old and taxing a 7 year old power supply can cause it to reset or become inoperative.
Here is some great information about computer power and how much you can use.
http://www.overclock.net/a/gpu-and-cpu-power-connections
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