Random Shutdown and then Rebooting

[Derder106]

Hi,

I've built a custom PC for gaming and had it running with no problem for 8 months.
However today, the system keeps randomly shutting down with everything going off, then after about 5 seconds rebooting like nothing has happened.
It has occurred several times, when I'm running games through Steam, also when the systems sitting idle.
I don't believe cooling is the issue due to having 3 intake fans and 2 outtake
I have also monitored the CPU temperature, so I know it is not that either.

Does anyone have any idea to why this is happening?

Thank you!

Specs:
Corsair 300R
MSI Z87 G45 Motherboard
I5-4670K @3.4GHz
Corsair H60 (Dual Fan)
G-Skill 8GB Ripjaws 2133Mhz
MSI GTX 760 2GB
120Gb Samsung SSD
650GB Samsung Hard drive
Light Script blu-ray Drive
XFX 650W XXX Edition
Windows 8.1

 

[badboyrog2]

first steam server and client can have a problem
second have you a really good internet speed and bandwith?? your driver for the lan is good?
third are you sure your psu is good?

 

[Derder106]

first steam server and client can have a problem
second have you a really good internet speed and bandwith?? your driver for the lan is good?
third are you sure your psu is good?

Hi,

My internet speeds are good (Fiber Optic 30mbs per second download) and the driver is sound.
My psu was bought from new and recommended to me as a solid component.