What's the difference? GPU-Z vs Furmark GPU Stress Test? Laptop Instant Shutdown

[wamendonesjr]

I'm currently restoring an old laptop of mine for sentimental reasons but it seems these pesky random shutdowns occur ever so often.
I tried several solutions before which led me to believe that the main culprit was my GPU
So...
I tried Stressing my GPU using *OCCT (not GPU-Z) and it would cause an instant shutdown but when I tried Furmark it would actually survive, I don't what's the difference between the two, why does this happen?
(Things to know )
on running GPU-Z stress test my gpu temps are normal but still cause my laptop to die.

on running Furmark stress test my gpu temps go up to 70 degrees but would continue running.

Laptop is an old G75VW that I'm trying to restore.

New MOBO
Tested each ram and clean their contact points.
Updated Drivers and BIOS.
PSU is about 2-3 yrs old.
CPU stress tests dont cause shutdowns and cpu temps are OK.
Tested using with Battery and No Battery.
Shutdowns occur when playing games or rendering on Unreal Engine.

[wamendonesjr]

Can someone help?

[xeromist]

You're saying starting GPU-Z causes an instant shutdown? All it is doing is reading data from the GPU firmware. You should make sure you have the latest GPU driver and perhaps try a different version of GPU-Z. If it keeps happening you may have to look at the Windows event log. There's a lot to interpret there so I suggest you Google on how to do that.

[wamendonesjr]

Sorry, it was meant to be OCCT instead of GPU-z

[wamendonesjr]

Oh sorry, what I really meant was stress testing the GPU on OCCT makes my laptop shutdown but not in Fulmark

[xeromist]

They work differently so there are a few potential reasons. One is that some systems specifically detect Furmark and limit power draw. So it's possible that OCCT is drawing too much power and triggering a power cut. This could be due to an undersized or aged power brick or a problem with the power delivery components inside the laptop.