New build help please

Case: Corsair iCue 5000X RGB (White)

CPU: AMD Ryzen 7 8-Core 5800X

CPU Cooler: Corsair iCue H150i Elite Capellix XT RGB

Motherboard: Gigabyte B550 Vision D-P

RAM: Corsair Vengeance RGB PRO 16 GB 3600 MHz ×2

GPU: PNY GeForce RTX 4080 VERTO 16GB GDDR6X PCIe 4.0

Storage: Corsair MP600 Gen4 PCIe 2 TB M.2 NVMe SSD

PSU: Corsair RM850x

Helping my son with his first build:
Well, got it put together. The standing problem is the pc will not stay on, it shuts down about 25 seconds into start up.
It shows the initial screen at start up and has prompted a boot os. It also will boot into bios [del] but it seems like no matter how far we get with it booting, it shuts down. I'm guessing a safety.

Here's what we've done:
Removed a mem stick.
Removed gpu.
Switched the 6 fans to commander from the Case.
[I read in here to split 3 and 3].
Checked all connections.

Not sure where to start. Not too hip on the lingo so might want to use full instead of abbr. I can include images or anything else needed. Thanks in advance.

 

Forgot to mention: unplugged 12V 8 pin connector from mb [top left] labeled cpu and pc did not shut down.

 

A couple thoughts.

First, concerning the 12V connector. That should be connected and it should work connected. So, verify that is the correct power lead from the PSU. Check your PSU's installation guide. The 8-pin (4 + 4) CPU cable connects to the motherboard. The 8-pin (6 + 2) PCIe cable connects to the graphics card "IF" the graphics card requires one. PNY offers several RTX 4080 16GB cards and we don't know which one. The only install guide I could find is very general, apparently for all their cards. That said, I would assume that card requires supplemental power since PCIe slots are limited to 75W.

These two cable connections are often confused but they are NOT interchangeable. So you need to first ensure you have the correct cables connected to the corresponding sockets on the PSU end, then do the same on the motherboard and graphics card end. While at it, ensure all cables (power and data) are secured tightly.

This may be common sense, but often overlooked is there typically is a thin protective plastic sheet covering the mating surface of the heatsink and/or CPU. This is to protect from scratches and grime during shipping and handling. This sheet of plastic MUST be removed before mounting the cooler.

Did you apply a proper layer of TIM (thermal interface material) on the CPU before mounting the heatsink? A "proper" layer is as thin as possible while still providing complete coverage. Remember, the most efficient transfer of heat occurs with direct metal-to-metal contact of the mating surfaces. The purpose of TIM is for the solid particles in the TIM to fill the microscopic pits and valleys in those mating surfaces to push out and prevent any insulating air from getting trapped between the device and its heatsink. Any excess TIM is in the way and counterproductive to the most efficient transfer of heat.

If your cooler block came with a pad of TIM pre-applied, that's fine AS LONG AS you removed any plastic protective cover and made sure the CPU mating surface was clean too.

If all that checks out, you will need to take everything out of the case and re-assemble the computer on a large, unfinished bread/cutting board to see if it boots there when you carefully and "momentarily" short the two "PwrSw" (power switch) pins in the motherboard's front panel I/O header with a small flat tip screwdriver.

Side note - for those who frequently work with computer hardware and don't like the thought of sticking a highly conductive, metal screwdriver into the heart of live electronics, consider getting a motherboard power switch. These are particularly nice if you don't have rock-steady hands, 20/20 vision, and excellent lighting.

If the system still does not work properly on the bread board, then I recommend trying to a different PSU. Since EVERYTHING inside the case depends on good, clean, stable power, you need to verify you are providing it - especially before considering replacing other components. The RM series from Corsair is a good line. But until Man can create perfection 100% of the time, even the best models from the best makers can have a unit that does not behave properly.

A common mistake by the less experienced and distracted pros alike is to insert one or more extra standoff in the case under the motherboard. Any extra standoff creates the potential for an electrical “short” in one or more circuits. The results range from "nothing" (everything works perfectly) to odd problems, to "nothing" (as in nothing works at all ). To add to the confusion, these issues may be intermittent, depending on heat, expansion/contraction of materials, as well as continuity/resistance through the contact point. Therefore, you need to ensure the case only has an inserted standoff where there is a corresponding motherboard mounting hole before you remount the motherboard in the case.

Note the latest version of the ATX Form Factor standard hopes to eliminate these issues by dictating where standoffs will go, not just where they may go. But not all existing boards or cases comply with those latest standards - yet. So, you still should verify you only inserted a standoff where there is a corresponding motherboard mounting hole.

Good luck and keep us posted.

 

Hello and Thank you Tony, yes I think it is a clue and if I had an ele diagram I'd be able to narrow it down even further so I'll be on the GB website digging around.
I think another clue is the timing on 'when' it shuts down.
Thanks for the tips