Please help with reboot problems on my PC

[woojtoos]

My Pc is rebooting randomly, on idle, at games, at working. There isnt any warning, just reboot (like somebody would press a reboot button). There is no blue screen, no artifacts on screen, no nothing, just reboot.
I change thermal paste, i change psu (before i have chieftec 400W), but it is still the same problem. What can it be ?
OCCT shows temperatures while testing ~46 degrees, in idle ~38. It is rebooting while testing.
There were no overclocking.
Big thanks for help.

My PC:
cpu: phenom II x4 925 (2,8MHz) + cooler similar to coolers on older athlon procesors (no heat pipes)
mb: gigabyte ga-78lmt-usb3
gc: radeon 4850 512mb
ram: 4gb ddr3 kingston kvr1333d3n9/4g
psu: xfx ts550

 

[Vic 40]

Can you try with a different gpu? Maybe lend one.

 

[woojtoos]

same thing, reboot

 

[Vic 40]

It can be the psu as well.Can you lend one to test with too?

Other wise try this,

Download hwinfo32,

http://www.hwinfo.com/download32.html

You can open hwinfo32,after that open the sensor window by marking sensors=V,after that click run,then click at the bottom "Logging start" ,after that choose a name and place for the log. like Hwinfolog at your desktop.Leave it open and do game/stresstest or whatever you do until a crash/reboot.The log will end at that point but will be saved.
After the restart upload the log to a site without to much crap (!),for instance dropbox,and leave a link to it here.You could also look at the log yourself with either excel or libre office calc.

You can also look at the voltages with a multimeter and a unused molex connector,Balck+yellow is +12V/black+red is +5V,or look into the bios,but the last option is only the voltage at that moment and without strain on the psu so only says so much.

 

[woojtoos]

Hi,
here is a link to log from hwinfo:
https://www.dropbox.com/s/sz83fc153qzx51h/test.CSV?dl=0

 

[woojtoos]

He is another one after some longer period of time (playing game)
https://www.dropbox.com/s/qldrfnn4wm4ettn/test2.CSV?dl=0

 

[woojtoos]

this one i cut some things from program, and try to make occt test, but it failed
https://www.dropbox.com/s/5bavtr27gebx3il/test4.CSV?dl=0

can somebody help?

 

[Vic 40]

Looked at those logs and as far as i can see are there no strange things.The only thing not displayed is the +5V reading,but since the other ones aren't out of spec do i suspect that this wil also be fine.The only way to know for sure is to use a multimeter.

Does the motherboard have the latest bios? Maybe something to look at.