Question Fans spin with 16 pin but doesn't boot

[manute771]

Motherboard: TUF Gaming X570-PRO Wifi II
CPU: AMD Ryzen 9 5900X
Cooler: EK 240mm AIO Cooler, D-RGB All-in-One CPU Cooler
Power: Corsair CX750F RGB, 750 Watt, 80 PLUS Bronze
RAM: G.Skill , F4-3600C16D-32GVKC RipJaws 5 Series Noir 32 Go (2 x 16 Go) DDR4 3600 MHz CL16 (2 of these)
Tower: Corsair iCUE 4000X RGB Mid-Tower ATX PC Case
Video Card: EVGA GeForce RTX 3060 XC Gaming, 12G-P5-3657-KR, 12GB GDDR6, Dual-Fan, Metal Backplate

This has been THE most frustrating build I ever did.

I was having overheating issues / booting issues but I have purchased a new motherboard, CPU, and cooler.

My issue is now...when I have both the 16 pin and 8 pin cable the system powers up and immediately shuts down.

When I unplugged the 8 pin (and only have the 16 pin cable connected), the fans spin but nothing happens. No MOBO lights (yellow, red, green, and white) that normally happen when booting although the MOBO light indicating power (the running light) is on. The cooler, video card, and PSU fans continue to spin BUT the case fans quit spinning after about 30 seconds.

I tried the paper clip test, works fine.

I can't believe this is happening. Two weeks of troubleshooting and nothing.

 

[DRagor]

when I have both the 16 pin and 8 pin cable

Specify what cables you mean. There are multiple types of 8-pin cables in PC, and none 16-pin cables.

 

[manute771]

Specify what cables you mean. There are multiple types of 8-pin cables in PC, and none 16-pin cables.

Red box is what I called the 16...sorry probably meant 24. Blue box is the 8 pin

Thanks and sorry for not being specific.

 

[DRagor]

Ok, now we have same picture of situation.

When I unplugged the 8 pin (and only have the 16 pin cable connected), the fans spin but nothing happens.

That's perfectly expected behavior.

I tried the paper clip test, works fine.

That means nothing unfortunately. Paperclip test only matters when it fails.

My issue is now...when I have both the 16 pin and 8 pin cable the system powers up and immediately shuts down.

How fast it shuts down?

I was having overheating issues / booting issues but I have purchased a new motherboard, CPU, and cooler.

More info here could help. What were the parts you used previously? Using same RAM and GPU in both builds, so we can assume GPU and RAM are in working condition then if they work fine in previous build?

Things to try:
Remove all but one stick of RAM
IF PSU has more then one EPS cable (or 8-pin as you name it) use the other one.
Remove GPU (obviously it will not post without it but question is if it will stop shutting down).