LeDoyen

I doubt the PSU is at fault there. that soft shutdown feature has been a thing since the dawn of ATX, in the windows 95 era and hasn't changed since. As long as the CPU will keep the PS ON contact closed, the PSU will not shut down, it only does that the CPU tells it to do. Some people have had luck on old boards with disabling windows fast startup, or by enabling fast boot in bios, but it's an annoying fault that can have a multitude of causes.

It's an X3D.. they run hotter due to the Vcache stacked on top. It's common to all X3D CPUs to be consistently warmer, and that throws us off when we're used to conventional CPU temperatures.

What is the old PSU? Are you using the cables that came with the RMe ?

just to be sure, the sticks are on slots A2 and B2 ?

you got that correct. the CPU cable goes to the EPS12v connector of the motherboard. you would soon realize if you force a PCIE connector in there. it is not keyed the same so you'd have to jam it in, and it would trigger the PSU short curcuit protection since the pinouts are different between the two. CPU = EPS12v PCIE = graphics card only

i am not sure the motherboard defaults to PWM. It's better to check in bios to be sure the PWM/DC switch on each channel is set to PWM. otherwise, if you get replacements they may get damaged (if that's the issue of course)

well, they shouldn't grind at all after 5 years. How are they controlled ? PWM or DC control? Using maglev fans on DC control can damage them.

there you have Corsair's cable chart for PSUs : https://www.corsair.com/us/en/s/legacy-psu-cable-compatibility Your AX1200i uses type 3 or type 4 cables for EPS12V (CPU cables). Type 3 is pretty old by now so you'll probably have an easier time looking for type 4 CPU cables.

the spec is 150w max per pcie connector, remembering that the card also draws some power from the motherboard ( often 50 - 60w off the 75 possible). so yea. loads of headroom with 2 cables.

the card has a power draw of 290W by default so, without overclock it would only need 2 cables. It's fine to use two cables with one pigtail yes. I wonder what they were thinking 😛 my 3090 (370W) only uses two connectors.

with this CPU, people often used 3000mhz without too many issues. 3600 is pushing it quite a lot. DDR4 was still new when it came out. it natively supports ddr4 2400. You can see the massive jump 3600 is. you could try enabling XMP, then dropping down the speed manually to have it run stable.

does the motherboard box say what bios version is installed? the original bios is F3, but the 14900k is supported starting with F4. From the manual memory initialization starts at post code 2B, but you don't even go there yet as you hang at code 11 which is CPU initialization. i don't see anything wrong with the layout you have besides the GPU using a single pigtail cable instead of two discrete cables (but you're not there yet since it doesn't boot at all and it's a moderate overload of the cable at worst). I would probably try to flash the bios to the latest version and see if the CPU kicks in (look in the manual for Q-flash, you can flash the bios without a working CPU on this motherboard).

there's a post there that explains the steps : https://rog-forum.asus.com/t5/intel-700-600-series/z790-e-gaming-wifi-ii-pl1-pl2-power-settings/td-p/996000 Factory values for the 13900k is Long duration : 125W, Short duration : 253W https://ark.intel.com/content/www/us/en/ark/products/230496/intel-core-i9-13900k-processor-36m-cache-up-to-5-80-ghz.html If the cooler works well, you can then increase the long duration power limit.

it is probably the bios settings, which on Asus often have power limits totally unlocked and multicore enhancement (overheating insurance) turned on. It's worth a shot having a look what those are set to (should be 253W PL2 on 13900k), and making sure MCE is set to "Off, enforce all limits". This CPU is very easy to cool if you don't let the motherboard cook it. Also, if you're not using a contact frame, it's a good idea to install one to replace the current CPU retention mechanism. It prevents CPU bending and allows for lower temps. Some see small gains, i personally reduced the temps on mine by a good 20°C under full load, but 10-15°C reduction with that alone isn't rare.

if i had to chose it'd be RMx. it's a good tier above, and doesn't get bad reputation for noisy fan 🙂