Only 1 or 2 out of 3 monitors now working after standby! (EVGAGTX960)

[WolfsburgEd]

I brought the machine out of sleep yesterday and only 1 of the 1 monitors was displaying.

If I disconnect that monitor then the other two will then display desktop.

I have had this set up working flawlessly since I built it mid last year.

I updated the GeForce driver yesterday but nothing changed.

I have just tried a replacement identical psu but that has not changed anything.

The really odd thing is that on Advanced display settings the number of monitors will be changing between 2 and 3 every second or two when there are all 3 connected but only one is showing as blue and only one has active display.

Any suggestions - I'm at a loss!

mobo - Asus Maximus Gene vii
CPU - i5-4690K 3.5GHz
PSU - Silverstone Stryder 500W evolution
GPU - EVGA GeForce GTX 960 4GB GDDR5
OS - Win10
monitors - Iiyama Prolite X2783HSU

nb - I'm not super proficient with settings etc so any responses please be detailed with instructions / assume little knowledge.

Additionally, the really odd thing is that regardless of what combination of sockets in the gpu I use for the monitors its always the same combination that will display / not display. If all three are plugged in then its only the middle one which I had previously set as my main monitor which will show. If I disconnect either of the other two then its still only that main centre monitor which displays. If I disconnect the centre main monitor then the other two come to life!

 

[WolfsburgEd]

I've now lost the ability to have even two out of three monitors working together. Again, it lost it after being on standby.

Does anybody have any thoughts on whether they think it would be the gpu, OS, PSU or mobo bios?

It takes an age to come back up from standby and chrome usually loses its top-bar graphics with the max/min and close icons and also the wallpaper frequently disappears when coming back from standby.