Question Bought a pc for a really good deal but im experiencing shutdown on load. Can't identify the source of issue

[KimchiChurro]

I purchased a used PC with the following specifications:
- GPU: 3090 palit gamerock
- CPU: 5950X
- Motherboard: ASUS Crosshair VIII Impact
- PSU: Corsair SF750
- RAM: 2x 32 GB Ballistix RAM
- Storage: 2x NVMe M.2, 2 TB SSD

The issue I'm facing occurs when the PC is under heavy load, causing the display to go blank with a "DisplayPort no signal" error message. Despite this, the PC remains powered on, with the motherboard and RAM decorative lights staying lit and the fans increasing in speed.

It's worth noting that the PC doesn't exhibit any issues when I'm simply browsing the web, watching videos, or playing less demanding games like League of Legends.

I tested the PC's load using Cinebench and found that the issue occurs whether I run a GPU or CPU benchmark. However, the GPU benchmark runs successfully with a significant undervolt. Overheating isn't the problem, as both the GPU and CPU stay below 80°C during the issue.

I used a power meter plug to measure wattage when the error occurs, and it never exceeds 550 watts, fluctuating between 400 and 550 watts—well below the PSU rating.

I also tested the RAM by using one stick at a time, but the issue persisted, ruling out RAM as the cause.

My conclusion is that the motherboard may be the culprit, though I'm uncertain if a faulty motherboard could even power on and cause this type of error. Have any of you experienced similar issues, and do you have any advice or solutions?

 

[geofelt]

I might suspect the psu.
Verify that all power cables are of the correct type and secured well at both ends.
This chart suggests that 750w may not be sufficient:

https://dlcdnets.asus.com/pub/ASUS/Accessory/Power_Supply/Manual/RECOMMENDED_PSU_TABLE.pdf

Your card is a highly overclocked version that needs 3 8 pin connectors which is more than normal.
And, use only one cable to the psu for each 8 pin; do not double up.

Also,
3000 series cards can have very high power peaks demands.
While the average power draw may be ok, the psu peak may not be able to cope.
The psu has a 7 year warranty.
Open a RMA with Corsair as a suspected psu issue and see how it proceeds.

Ultimately, I think you may need a stronger psu.

 

[KimchiChurro]

I might suspect the psu.
Verify that all power cables are of the correct type and secured well at both ends.
This chart suggests that 750w may not be sufficient:

https://dlcdnets.asus.com/pub/ASUS/Accessory/Power_Supply/Manual/RECOMMENDED_PSU_TABLE.pdf

Your card is a highly overclocked version that needs 3 8 pin connectors which is more than normal.
And, use only one cable to the psu for each 8 pin; do not double up.

Also,
3000 series cards can have very high power peaks demands.
While the average power draw may be ok, the psu peak may not be able to cope.
The psu has a 7 year warranty.
Open a RMA with Corsair as a suspected psu issue and see how it proceeds.

Ultimately, I think you may need a stronger psu.

I was going by this assumption aswell, until i ran the CPU benchmark on cinebench, while doing this i was monitoring the gpu usage, using afterburner and window + g, the issue took longer to occure than the cinebench GPU benchmark but it still occured despite the GPU usage being 0-1%. this causes me to think that maybe it isn't the PSU.

regarding your cabling comment, I have also thought the cabling may be the casue and have attatched the cabling i used for the gpu, the circled 8pins are the ones i use to connect to the gpu. is this fine ? https://ibb.co/cJjqcPZ

 

[geofelt]

If this is your gpu, the specs recommend 850w and 3 8 pin connectors:

::Palit Products - GeForce RTX™ 3090 GameRock ::

Palit New GameRock, also known as “The Dazzling Angel,” is specially designed for enthusiast gamers who desire to have ultimate gaming experience and pursue maximum ARGB lighting environment. GameRock series provide the best gaming features, ultimate thermal solution and premium graphics card...

www.palit.com

Connecting two 8 pins via one cable may overload a single cable.