Currently, my rig has 750W PSU. With 3 cards running 100%, power draw at the wall is 590W. The cards I'm using are RX470 4GB, and in GPU-Z the power usage for each card shows as 95-105W while I'm mining.
I'm wondering if I'm able to add another GPU, increasing wattage by ~105W, making my rig run at ~695-700W on a 750W PSU? Is this trying to put too much load on the PSU? I know basic mathematics say it's ok, but I don't know enough about PSUs to know if it is reasonable of me to expect my PSU to be under 700W load 24/7. Thanks for the help!
As Phil said, if 3 cards are already at 590W for you, your cards are drawing 160W atleast. Adding another card would get the total to 750W, which may run but is not recommended at all. On a 750W PSU aim to consume no more than 600W in the long term.
Now, I do have several 5 card rigs that have been running on Corsair 750W Gold PSU's for 8 months problem free, but all my cards are heavily undervolted/underclocked.
Each card consumes 55-60W (GPUZ) and 100W at the wall producing 26mh/s.
If you want to push your cards to 28-29mh/s though, a 750W PSU wont cut it, because power consumption goes up exponentially as you overclock.
also sometime a overclocked pushed card goes runaway it resets and basically maxes say it was pulling 140-160 pushed with hard clocks all of a sudden it pulls 180-190 till it over heats and if you psu was pushed hard the rig shuts down.
@ op
I try to never use a card at 80 percent of its max. I shoot for 70% so I card listed at 150 tdp I try to never let it go over 95 watts/ The software numbers from gpu-z are okay but low.
I try 1 card at idle and check the entire rig on a kill a watt say or 30 watts plus check gpu-z say 7 watts for the card
I then mine with the rig and I check kill a watt say 190 for the rig plus check gpu-z say 110 watts for the card
at the meter I went up 160 watts at the gpu-z I went up 103 watts so I know the gpu-z is off