What is the maximum safe current for Mac Pro PSU? I regularly put my 2010 Mac Pro under pretty heavy usage, maxing out the 12 core CPUs and GTX Titan Black.  I can monitor the voltage and current using iStat Menus, but I'm looking for a specification of how much current is allowable for each device.  The readings that concern me are Vcore, PVTT, PSU (PSMI), PCIe Slot and Boost.

I believe this system has a 980W PSU, which is 82 amps at 12V.  The readings shown here add up to much higher than that, but my 120V UPS shows that the whole system is using less than 700W.  Confusing.
Not all of the listed items have a voltage of 12 V. E.g the HDD+ODD has only 5 V and the CPUs have a much lower voltage. According to Intel the voltage of the Xeon® Processor X5670 maxes out at 1.350 V and the TDP is 2 x 95 W (and not 2 x 12 V x ~46 A = 1104 W).

So just adding all currents and multiplying them with 12 to get the wattage is not appropriate here.