Unexpected PSU shutdowns

[LyondellBasell]

Recently swapped my pc from the reference blower coolers and an Kraken AIO to a full custom loop.

Boots fine and can complete a TimeSpy stress test no problem.

 

However, when I go to play Bioware's latest fiasco, I get unexpected shutdowns.

At first I attributed it to an over-sensitive Asus Anti-surge; upon POST, the warning came up. But with AAS switched off, the PC continues to shut off when exiting menus back into the game, or in the middle of combat.

I have the SeaSonic 1050 SnowSilent, is 1050W truly not enough to maintain stable voltage and avoid surging?

If so, would a 1200W unit be enough to solve my probem?

 

System specs:

 

Windows 10 64-bit

SnowSilent 1050W

i7-6700K, OC 4.5 GHz

Maximus VIII Formula, UEFI BIOS rev. 3401 - 2017/3/31

2 x Titan X Pascal, OC 2.05 GHz

32 GB Dominator Platinum

950 Pro M.2

850 Pro 2.5"

2x WD Black 3.5"

2 x Laing D5

3 x 120 Corsair ML

2 x 140 Corsair ML

4 x 140 NZXT FZ

3 x 200 NZXT FZ

[NoRomanBatmansAllowed]

What does Furmark  & Prime95 do to it?

Does it shut down then?

[LyondellBasell]

I haven't tried Furmark, but ran Prime95 for 3 hours yesterday. Package temp maxed out at 63C.

TimeSpy had both cards at 95-100% load and power usage, but no shutdown occurred.