Question Whole PC not working right

[motzman]

Hello I need your help I currently bought a new psu (BE Quiet! Pure Power 12M 750W ATX 3.0) and I installed it today.
My current specs:
CPU: AMD RYZEN 5 2600X
CPU COOLER: Stock AMD
MAINBOARD: ASROCK B450M-HDV ATX 2.4
GPU: Radeon Nitro Sapphire RX 590
RAM: 2X8 GB G.SKILL RIPJAWS DDR4
SSD: 1 TB Samsung SSD 860 QVO
PSU: BE Quiet! Pure Power 12M 750W ATX 3.0
Six Corsair Fans, all built into Lian li x 8auer case

but when I turn on the PC just the fans start spinning and the motherboard gets power I think, because when I plug my phone in to load or headset it loads. But heres the catch my CPU FAN wont spin and my GPU wont start, but if I plug my DisplayPort to HDMI Cable (The DP goes to the monitor and the HDMI to the GPU) while power is on my cpu fan starts spinning. Also the GPU starts but it wont display something on the monitor. So if i unplug the pc but leave the hdmi cable in the gpu turns off but the cpu fan isnt shutting down. So im completely off power just the monitor has power! The psu cable is not plugged in! I already tried with a DP to DP but the GPU and CPU wont start.
Could it be that the psu is ATX 3.0 and the Motherboard ATX 2.4 compatible and therefore this error occurs? Or is it something other?
Thanks for your help in advance!!

 

[Zerk2012]

Hello I need your help I currently bought a new psu (BE Quiet! Pure Power 12M 750W ATX 3.0) and I installed it today.
My current specs:
CPU: AMD RYZEN 5 2600X
CPU COOLER: Stock AMD
MAINBOARD: ASROCK B450M-HDV ATX 2.4
GPU: Radeon Nitro Sapphire RX 590
RAM: 2X8 GB G.SKILL RIPJAWS DDR4
SSD: 1 TB Samsung SSD 860 QVO
PSU: BE Quiet! Pure Power 12M 750W ATX 3.0
Six Corsair Fans, all built into Lian li x 8auer case

but when I turn on the PC just the fans start spinning and the motherboard gets power I think, because when I plug my phone in to load or headset it loads. But heres the catch my CPU FAN wont spin and my GPU wont start, but if I plug my DisplayPort to HDMI Cable (The DP goes to the monitor and the HDMI to the GPU) while power is on my cpu fan starts spinning. Also the GPU starts but it wont display something on the monitor. So if i unplug the pc but leave the hdmi cable in the gpu turns off but the cpu fan isnt shutting down. So im completely off power just the monitor has power! The psu cable is not plugged in! I already tried with a DP to DP but the GPU and CPU wont start.
Could it be that the psu is ATX 3.0 and the Motherboard ATX 2.4 compatible and therefore this error occurs? Or is it something other?
Thanks for your help in advance!!

Did you only use cables that came with the new power supply?

 

[motzman]

Yes

 

[Ralston18]

This:

"So if i unplug the pc but leave the hdmi cable in the gpu turns off but the cpu fan isnt shutting down. So im completely off power just the monitor has power!"

If pc components are running when the pc/PSU is unplugged from the wall outlet then that suggests to me that there is an electrical problem somewhere.

Possibly a ground loop in some manner: Device A connected to Device B connected to Device C connected to Device D connected to Device A again.

Could be via video, audio, network, USB, coax, UPS....

Sketch out simple diagram of all components and connections. If you can find a loop then disconnect that loop in some manner.

Determine if the problems end.

I would suspect some problem with the hdmi cable.

Any "Y" adapters being used anywhere?

 

[motzman]

I fixed it I just was dumb! I didnt plug in a 8pin connector into the psu I didn't saw it was under the psu. Now it works!
thanks for your help!