GPU Card causing PC reboot

[nakedtons]

I have no previous problems with my GPU card which is just barely 2 months old and my PSU is only about 4 months old. However, I started experiencing sudden computer reboots when surfing the internet and launching games. I did a check and found that the PCI-E cable connected to my GPU has come a little loose which might explain the problems it is causing and really hope it is!
I took screenshots of my GPU status on GPUZ. The 12V rails is not showing which might be due to a Windows 10 problem. I am a noob at monitoring my GPU status and need your opinion if my GPU and PSU supporting it are okay. Screenshots are taken from GPUZ with my GPU on idle.
I also noticed that my Sapphire card runs a little hot on intense games despite the dual fans and need a recommendation on the fan speed I need to adjust to avoid overheating and a computer reboot. Appreciate your answers!

Here are specs for my gaming rig which I had just assembled in July on a tight budget.

Motherboard: Asus M5A78L-M LX V2
CPU: AMD FX 8320
CPU Heatsink: Coolermaster V4GTS
PSU: Seasonic G-Series 750W
RAM: Kingston DDR3 1600mhz 8GB
Harddrive: 2 X 1 TB Western Digital Black
Optical Drive: Liteon DVD-R/RW Writer
GPU: Sapphire r7 265 Dual X

 

[Forgotten031511]

PCI-E cable? PCI-E is a slot, the only cable that connects to it is the Power Cable from the PSU.

A total system reboot does not usually indicate a loose power cable to the GPU (most of the time anyway). Your main culprit is heat with rebooting issues. Either your CPU or GPU is overheating and the BIOS is sending a reboot signal to prevent damage to the unit.

Other than that, your PSU could be failing in general...the loose cable may have caused inconsistent power issues to the PSU and damaged it (not likely, but possible).

As you have already checked your GPU heat (screen shots), check your CPU temps.

 

[nakedtons]

PCI-E cable? PCI-E is a slot, the only cable that connects to it is the Power Cable from the PSU.

A total system reboot does not usually indicate a loose power cable to the GPU (most of the time anyway). Your main culprit is heat with rebooting issues. Either your CPU or GPU is overheating and the BIOS is sending a reboot signal to prevent damage to the unit.

Other than that, your PSU could be failing in general...the loose cable may have caused inconsistent power issues to the PSU and damaged it (not likely, but possible).

As you have already checked your GPU heat (screen shots), check your CPU temps.

It is the PSU cable connecting to the GPU which came loose a little. I figure it couldn't actually be the fault of my PSU as it's only 4 months old and from Seasonic G-Series. 750W is more than sufficient.
Here is a screenshot of my CPU temp at idle. You can see that the reading is pretty good. I don't see a problem with my CPU overheating when gaming and I am using an aftermarket cooler too. If the problem occurs again, the problem is probably due to an overheating GPU due to intense gaming! There are suggestions that I manually increase the GPU fan speed on ATI control catalyst but I do not know what is the recommended speed that I need to adjust to during intense gaming!

 

[Forgotten031511]

Run a Stress Test and Monitor Your System...see what/where/when the issue occurs.

3DMARK: http://www.futuremark.com/support/downloads
UNIGINE: https://unigine.com/products/benchmarks/valley/

 

[Forgotten031511]

Also, having the PCI-e Power Cable loose COULD cause damage to the PSU.

If you had a power sensitive device poorly connected for months, you would expect that to cause problems, same concept here.

 

[nakedtons]

Also, having the PCI-e Power Cable loose COULD cause damage to the PSU.

If you had a power sensitive device poorly connected for months, you would expect that to cause problems, same concept here.

I couldn't understand how a loose cable could damage the PSU! I just guess that a loose cable to the GPU just meant that the GPU did not get sufficient power from the PSU, nothing more. Maybe you could elaborate further?

 

[Forgotten031511]

OK think of static electricity, if you shuffle along carpet and touch something in the dark you see an arch, right?

When the cable is loose, power is flowing but the connectors are not solid. When the connection is not solid, the protection around the connection is not there. This allows the "possibility" for the power to arch elsewhere. Electricity always takes the path of least resistance. Since your Graphics Card has resisters (think of the name) it can reduce power flow when/where needed. The PSU still sends the same amount of power though. So the electricity "may" take another path with less resistance. It "could" then arch out of the connectors and have the power connect somewhere else on the card.

If you arch static electricity to the card you could fry it right? Well, think of how little power a static shock is compared to a 750W PSU. The arch goes further and with more power; hence, potential for damage.

 

[nakedtons]

OK think of static electricity, if you shuffle along carpet and touch something in the dark you see an arch, right?

When the cable is loose, power is flowing but the connectors are not solid. When the connection is not solid, the protection around the connection is not there. This allows the "possibility" for the power to arch elsewhere. Electricity always takes the path of least resistance. Since your Graphics Card has resisters (think of the name) it can reduce power flow when/where needed. The PSU still sends the same amount of power though. So the electricity "may" take another path with less resistance. It "could" then arch out of the connectors and have the power connect somewhere else on the card.

If you arch static electricity to the card you could fry it right? Well, think of how little power a static shock is compared to a 750W PSU. The arch goes further and with more power; hence, potential for damage.

Problem solved after I had tighten the loose cable! No more sudden reboot when intense gaming!