Desktop becomes unresponsive after idling for a short time

[species8472]

I couldn't find a troubleshooting forum so I'm putting this here.

So I have a peculiar problem that I'm hoping someone can help me with. I recently built my first gaming computer. Runs great, except for one thing; if it idles too long it becomes completely unresponsive and I have to either hold in the power button or hit the reset button. The screen remains on (it glows) but it is blank. I have the power button set to put it on hibernate when pressed, but when it gets stuck, hibernate won't work so it isn't just the monitor failing to come back on. If I move the mouse or press a button on the keyboard right after the screen goes off it comes right back on. It's only after I've let it go for a little while that it just stops responding. Any ideas what this could be?

Motherboard: GIGABYTE G1.Sniper H6 LGA 1150 Intel H97

RAM: G.SKILL Ripjaws Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL9D-8GBRL

Graphics Card: EVGA 04G-P4-2983-KR GeForce GTX 980

CPU: Intel Core i5-4690K Devil's Canyon Quad-Core 3.5GHz LGA 1150

I think those are the essential specs for a problem such as this. Let me know if you guys need more.

 

[Outlander_04]

what OS?

and does it behave the same way when you restore the default power scheme?