PSU surges and wattage for 970+1070+1080ti

[twigalicous]

A few days ago my pc started shutting down while mining. After the fourth time, i had a message on bios screen stating that power surges were detected and system was shut down to protect it. I am using a Corsair HX850W, Z97A mobo, 970, 1070 and 1080TI. The 1070 and 1080 are bumped down to 85% power usage. I have stopped mining for fear of damaging my system but i have been able to play light duty games without shutdown. Couple questions. From the numbers I have come up with, I am using about 750 watts. Is that enough to wear out PSU over time? I have only been mining for 4 or 5 months but have had the PSU for maybe 6-7 years. A little over 2 weeks ago, lightning hit my neighbors tree. It didn't seem to affect anything in my house but now I am wondering if it may have damaged PSU?

 

[jay32267]

It's difficult to say without doing any tests.
What I would do is be checking the voltages of the PSU under load with a multimeter or if that isn't practical for you I would use some software.
Or you might just want to swap in another PSU.