Rig Help

So I have a rig that was running flawlessly with 4 msi rtx 3070 gaming x trio, a 1200 watt titanium corsair psu, msi z390a pro mobo, an intel i5 9th gen cpu. I obtained a 5th indentical card (msi rtx 3070 gaming x trio) and added it to the rig. When mining RVN my rig will shut down after 30 -120 minutes. I have the cards OC'd at +100 core +1100 memory, 65% power limit pulling 155W a piece, 75% fan speed. The cards never go above 53°C. TPD at the wall hovers between 795 and 850. Is this too much for this psu despite following the 80% load rule? I tried lowering the power limit further so that each card was only pulling 130watts, but still ran into the restarting issue. I also tried removing T-rex miner and reinstalling. I do not have this issue when mining ERG even if I set the OC settings to draw the same amount of power… If I disconnect the 5th card it mines RVN without restarting which makes me think this is a psu issue, I'm just confused why this psu can't handle it (assuming that is the issue)