Possible psu failure

[SlAy3r41]

Hi knowledgeable ppl,I need some advice plz.
I keep getting a black screen on both my monitors when I'm on pc surfing or being on games.The black screen happens after around 10 mins of being on.There's still power to both monitors as I can see the power light's are still lit.The pc is still powered on.
Along with that problem I also have a problem where my bios keeps resetting itself back to default settings.I don't have any overclocking except for XMP.I'm not sure if they are both related or not!!The bios resetting itself was also doing it on a Asus maximus vii ranger mobo.I have changed the cmos battery also.
My system is as follows,
Cpu,Intel 4790k.
Mobo,Asus maximus vii formula.
Ram,Corsair vengeance Pro 2400mhz paired,also has Corsair ram cooler too.
Aio,Corsair h80i.
Ssd/hhd,1 256gb ssd/1tb ssd /2 1 tb hhd's.
Gc,Asus expedition 1060 6gb.
Psu gigabyte p850gm.
I've got a feeling that it's the psu as I was having the same problem with the bios on both mobo's but still with the same psu.
Plz bear in mind that I'm not really pc savvy lol.
Thx for ay advice given

 

[SlAy3r41]

In order of questions
1st,no not updated display driver.
2nd,black screen just started tonight.
3rd,yes both monitors turn on at the same time,yes I tried 1 monitor at a time,same results.1 monitor is rated @165hz,my 2nd monitor is rated @65hz,both are 1080p.
4th As it goes yes I did move the tower,I put the 1tb ssd in yesterday,but all was working till this happened,but will check that gc is securely installed.
5th I didn't think that doing the XMP setti gs would need the voltages changing too as I thought the mobo does the voltage aswell,but if that's not the case can you maybe tell me what voltage it should be for XMP profile,if that's possible.
Thx for your help it's very much appreciated

 

[SlAy3r41]

Thx for all the suggestions,I will let you know how it goes when I look at my rig.Have recently knackered my back so can't lift or bend lol.