Computer shuts down while gaming

[ciolac.iulius]

Hello everyone, first of all I'm sorry about my english and the mistakes I'll make

The problem I have with my computer is that whenever I play a game that has high graphics, it shuts off immediately as if unplugged. Now I can still play some old games and such, but it's really bothering me.
I went to a PC-reparator, and they quickly looked at the problem, called and told me it was the GPU. I had a Geforce 980.
So today I received my new GPU, a EVGA Geforce 1070ti

My specs are :
CPU : i7-4790K @4.00GHZ
GPU : EVGA Geforce 1070ti
PSU : CoolerMaster G650M
Motherboard : Z97 PC MATE
OS: Windows 10, 64-bit
RAM : 8GB DDR3
I built this PC in 2014, so everything is from then except the new GPU

Now the PSU I have has a lot of dust in the CPU radiator(?) wich I'm going to remove tomorrow, but I doubt that's gonna fix the problem.
So far I've already tried :- Putting the GPU on the other PCI slot
- Older drivers and/or reinstalling new ones for the GPU; updating the other drivers
- Running the games with the integrated graphic card, wich works, but as you except very slowly
- Switching between the different power cables that power the GPU
Also, I used OpenHardware to look at the temperatures the moment it shuts down, but neither the CPU nor the GPU go above 50 degrees.

Thanks in advance for your help

 

[geofelt]

Under high graphics load, a graphics card will draw more power.
Your new GTX1070ti even more than the GTX980.

Possibly your psu dust is the issue.

Can you test with a known good psu?
Your psu is aged and they can deteriorate.
If insufficient clean power is available, you can get artifacts or other symptoms.
The unit is not considered one of the better Coolermaster units anyway.

If your psu needs replacing, I like the Seasonic focus units, 550 or 650w whould do it.

 

[ciolac.iulius]

Unfortunately I have no other hardware on hand to test anything, that's why I'm asking here, I'm currently saving up ( again ) to buy a PSU in case, and I wanna be sure that it's the issue

I never got any visual problem though, no bugs or artifacts, and if the PC lasts a few seconds more than usual, the game runs very smoothly like it should

 

[geofelt]

1. can a friend lend you a psu for testing?
2. Will a shop swap in a psu for testing?
Perhaps the one that identified the need for a different graphics card( perhaps not if they made a mistake)
3. When it comes time to buy a psu, buy from a place with a good return policy. Expect to pay 15% restocking.

 

[ciolac.iulius]

I will try and get a hold of a working PSU, but that doesn't help me considering there are few chances i'll get one

 

[ciolac.iulius]

Is this a good enough PSU ? Seasonic Alimentation PC FOCUS Plus 850W Gold - Modulaire ? what is " Modular " ? Do I really need to care about that ?

And, from what I saw the PSU is only the "powerhouse" while I have my radiator on the CPU which is also named CoolerMaster, will I need to remove it too ? or is it a different piece ?

 

[ohiou_grad_2006]

The radiator should be a separate part.

 

[geofelt]

The Seasonic focus 850 gold is an outstanding power supply.
850w is more power than you need, but the only real negative is the higher cost vs. something like a 650w unit which should do the job equally well.
A power supply will only use the power demanded of it, regardless of the max capability.

The cooler on the processor is necessary and should not be removed.

 

[ciolac.iulius]

Alright, so I've got one choice left : is it the PSU or the Motherboard ? considering how hard it would be to find a decent motherboard that goes with my build and my DDR3, I hope it's the PSU, but is there a way to be sure ?

I changed the thermal paste today, no changes observed

 

[ciolac.iulius]

?