AX860 not enough for 3090

[Born_2_Kill_83]

Feel like a need a second pair of eyes on this, I'm also going to post in the O/C section as I'm not sure where the problem lies.

I'm getting power off/restarts in Hunt Showdown, and only Hunt which is the odd thing, I've recently completed 70+ hours in Cyberpunk without a single problem from what I remember. That game has massive media on being buggy so I may of had a shutdown and put it down to the game on that occasion.

My system consists on the below:
3090 (founders) @ 120% power +125 core
8700K @ 5.0g 1.31v (8Pack binned delidded) with Corsair H150i AIO 6 120mm RGB fans
Gigabyte Gaming 7 Z370 + 16GB 3600mhz
3 further 120mm RGB fans for case
Multiple RGB strips and controllers
2X SATA SSD, 1X M.2 SSD, 1X spun drive

I have tried the following:
Checked all cabling to the PSU and MB is seated correctly
Stressed CPU overclock for several hours in Prime95 OCCT, Linpac and AIDA64
Stressed GPU for several hours across multiple benchmarks and games
Re-seated AIO to remove air bubbles
Re-applied thermal paste X 2
Stressed Memory

Max temps on GPU are 72C, CPU highest core in game 78c, VRM 72C.

A online PSU calculator suggest I need a 780W PSU

Now the reason I'm now questioning the PSU while although on paper is should be enough it is over 3.5 years old and has had a hard life. What's more is if I remove my GPU overclock and put it back to 100% power, everything is fine, if I run my CPU at stock speeds all is fine. It feels like I'm hitting a power peak and the system is crapping out. Could I be wrong? why only in one game that's the thing that's getting to me. Warzone fine, Assassins Creed fine.

Thanks for reading my wall of text

 

[Born_2_Kill_83]

Thanks for the input guys, I think I'm going to go PSU shopping, at least if I buy one off an online retailer like the rain forest I can return if I still get power offs.
Soon as I drop power on the GPU or CPU it becomes more stable, I can play for longer but I'm still getting crashes, could just be a buggy ass game as well.

Future proofing for an I9 or equivalent what should I go for to pair it with my 3090, 1000w or just jump to a 1200, or is that wasting money

 

[Born_2_Kill_83]

If I had to guess, I’d say it’s that your overclock is unstable in certain games. Maybe dial it back 25-50 MHz, and see if that fixes the issue.

This is what I thought, I first dialed it back to 100 core (-25) = crash, then I ran at stock clocks just 120% power = crash.

 

[Born_2_Kill_83]

Interesting that there are people happily running 3090's on 850w PSU's, without an issue, or at least an application that's found the issue yet. Mine's fine in 70 hours of Cyberpunk which really pushes my machine CPU and GPU, yet a 3 year old Crytek game spikes the hell out of it.

 

[Born_2_Kill_83]

I have replaced with a RM1000X and the issues has gone away. The AX860 is now being RMA'd though I'm not sure if it's faulty or not.