syops said:



As for how much power can be drawn from the 6 pin connector on the Mac Pro 4,1 | 5,1 , it makes sense the power protection will shut the machine down when the power supply limit is exceeded. The Mac Pro 4,1 | 5,1 has a 980 watt power supply. So if we where to use 375 watts just for the GPU, there would be 605 watts for the system. In my case I have two x5690s, If the CPUs used the max wattage there would be 345 watts left to run everything else. I think there is still enough margin on the power supply.



The pin out of the mini 6 pin PCIe AUX on the MAC PRO 4,1 | 5,1. looking at the pin diagram, you can see the only pins that provide power on both the 6 and 8 pin PCIe AUX are pins 1,2 and 3. On the 6 pin plug, pin number 2 may or may not be connected. See note in diagram.

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Yes the number 2 pin is connected on the MAC PRO 4,1 and 5,1. Electrically by jumping the extra ground and sense as depicted in the picture you signal the GPU it is a 8 pin connector. If there are only two power pins in this configuration you may run into a overload issue, but the Mac Pro has all three pins powered. Yes you can draw the maximum 375 watts for a single GPU on the MAC PRO 4,1 | 5,1.



Here are the meter tests showing all three power pins connected with power.



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Bit-Tech did a review on the Strix 980 Ti OC. Looks like the GPU is using well over 300 watts.



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https://www.bit-tech.net/hardware/graphics/2015/08/07/asus-geforce-gtx-980-ti-strix-review/10 If the STRIX 980 Ti OC can hardly pull 275 watts, why would the manufacture put a more expensive 8 pin connectors on? Why not a 6 and a 8 pin like the newer lower power Pascal cards? I think it is for the folks that really like to overclock their equipment. So this is why ASUS put the bigger power plugs on the card.As for how much power can be drawn from the 6 pin connector on the Mac Pro 4,1 | 5,1 , it makes sense the power protection will shut the machine down when the power supply limit is exceeded. The Mac Pro 4,1 | 5,1 has a 980 watt power supply. So if we where to use 375 watts just for the GPU, there would be 605 watts for the system. In my case I have two x5690s, If the CPUs used the max wattage there would be 345 watts left to run everything else. I think there is still enough margin on the power supply.The pin out of the mini 6 pin PCIe AUX on the MAC PRO 4,1 | 5,1. looking at the pin diagram, you can see the only pins that provide power on both the 6 and 8 pin PCIe AUX are pins 1,2 and 3. On the 6 pin plug, pin number 2 may or may not be connected. See note in diagram.Yes the number 2 pin is connected on the MAC PRO 4,1 and 5,1. Electrically by jumping the extra ground and sense as depicted in the picture you signal the GPU it is a 8 pin connector. If there are only two power pins in this configuration you may run into a overload issue, but the Mac Pro has all three pins powered. Yes you can draw the maximum 375 watts for a single GPU on the MAC PRO 4,1 | 5,1.Here are the meter tests showing all three power pins connected with power.Bit-Tech did a review on the Strix 980 Ti OC. Looks like the GPU is using well over 300 watts. Click to expand...

I am totally open minded to your theory. And I want that's the truth indeed (I am sure get the correct cable is much much easier / safer than the Pixels mod). However, your post didn't shows that any mini 6pin was delivering 150W, nor your 980Ti was pulling way over 300W from the cMP. That 337W difference in that graph is the ENTIRE system, including more demand on RAM, CPU, etc. Unigine Valley is not (and cannot) only stress the GPU but leave everything idle. And don't underestimate the power consumption on the CPU, there is a big difference between true idle and only 1 thread is being used. Especailly that 5960X (140W TDP) was OCed to 4.2GHz and over volt to 1.25V.The CPU can easily pull way more than you believe. I personally believe the following review is a more appropriate one when calculating the 980Ti's power consumption.I totally understand that you showed us that there are 3 pins connected. However, so far, all experience shows that once the demand over 120W on any mini 6pin, the cMP can shut itself down anytime. We are not talking about "in theory" but the real world. I also understand that a "correct cable" is required. However, quite a few users here did try the mini 6pin -> 8pin, seems none of them so far can really draw 150W from only one mini 6pin. I doubt if no one get a "correct cable" so far.I know I should not ask you to further OC / over volt your 980Ti and then run Furmark to try the max possible power draw on your system. And I don't want to risk your system as well. However, it seems that you are the only person that have the 100% correct cable on hand and able to run the test properly. If you unable to show us the definitive prove, it's really hard to judge if your theory really work on the cMP.Once again, I am open minded to your theory. I did study both the Mac Pro 5,1 manual and the corresponding technician guide again, but unable to find any info about the limit of the 6pin. However, until anyone provide a reliable proof, I will still treat the real world limit of those mini 6pins are ~120W. That's the best we can do so far with lots of users experience. I wish you can successfully push this limit further, and tell us that all we need is just a correct cable.