PC shuts down and reboots on load

[yltmas]

HI, my PC shuts down when on load, and then reboots immidiatly after, i first noticed it some time ago, playing Cities Skyline(not the most demanding game) it might be after some seconds of playing or after alf an hour, but it still does.
I really don't think is a straight forward heating issue, since the temps aren't to high when it' shuts down(sometimes it can't even reach 50° on CPU nor GPU).

What i did up to now:
Clean the machine.
Reset the system.
Tried unplugging secondary stuff(like other HDs, and DVD-player).

This is the config:
PSU: THERMALTAKE smart SE 630W ATX 80+ BRONZE
RAM: DDR3 Corsair vengance BLUE 1600MHZ 8GB(2x4) CL9
MOTHERBOARD: Gigabyte GA-Z97P-D3/Rev 1.1
CPU: Intel i5-4950 3,3GHz 6mb
GPU: VGA SAPPHIRE VAPOR-X AMD RADEON R9 280X MEMORY GDDR5 6000MHz 3GB
MEMORY: one SSD, 2 HDs

What can i do? Wich component might be the faulty one?

I know the PSU is not one of the best ones, but for what i know any of the parts could be broken or worn by time.(i'have had the pc for around 4 years and 1 year ago i replaced the motherboard for another issue).
Not having a much money i don't want to spend money replacing a working component and still face the same issue.

 

[jay32267]

I am leaning towards the PSU as the problem.

Here's why. When you apply load, and the PSU is the problem, the voltage(s) will drop and your machine will crash.

Once it crashes, the load goes away, the voltages come up, and you boot.

I would monitor the voltages up to, and while it crashes (if you can).

You want the voltages to be with 5% of nominal...except...10% for -12V and -5V....but 5% for everything else.

 

[Gadhar]

Jay is correct, the psu is the likely culprit. If you are not able to test it then maybe a friend has one your could borrow to see if the issue is the same with a different psu. If you budget allows I would order a new psu and be done with it.

 

[yltmas]

I am leaning towards the PSU as the problem.

Here's why. When you apply load, and the PSU is the problem, the voltage(s) will drop and your machine will crash.

Once it crashes, the load goes away, the voltages come up, and you boot.

I would monitor the voltages up to, and while it crashes (if you can).

You want the voltages to be with 5% of nominal...except...10% for -12V and -5V....but 5% for everything else.

How can i montior the voltages, is there any software way?
Do you have any suggestions for a PSU replacemant for my config?
i've read that the SeaSonic M12II 620 Bronze 620W isn't bad, and if it is 50€ seems a really good price, but i'm not sure if it would be any good for my specs.

 

[Gadhar]

you could use cpuid hwmonitor. It is free and you can see your voltages. There may be, and probably are better choices that Jay could elaborate on. As for the SeaSonic PSU I have that very model on my spud computer and it is a good performer, a bit dated, but still a solid PSU. It powers my oc'd FX8350 which sits at 4.7ghz without a problem.