Ok you should check your BIOS and see if the x16 slot is set as first display (default). And also please change the setting to x16 3.0 from Auto if there's any. Clean your GPU and the connectors thoroughly including the slot, canned air will do the job.
And.. don't forget to set your energy options to "high performance" mode in the windows control panel.
NOTE: Silly question but I'm assuming that you are using the x16 slot bc it won't work if you put your GPU on the other slots.
Let me know what happens after that.
Hey mate sorry i forgot about this post i have been busy.
I am using the 16x slot because its faster and others are only 8x. . next time it happens ill check bios settings as suggested. although its weird that re-seating GPU works.
PC has been working great up till today where It happened again.
I accidentally bumped the desk hard and the pc reset. After booting up the bus interface was showing @16x 1.1 with render test.
ran a 3d mark and got 12266.
I re-seated the GPU and it didn't solve the issue.
Then i tried to blow in the PCI-E slot and put GPU back in and it worked again back up to @16x 3.0.
3d mark back up to 13092.
gonna hit it up with some canned air on the weekend and see how it goes.
The motherboard is still under warranty for another year, however i worry that if i RMA they wont find an issue as its so intermittent. and will get the same board back.
Update: I am not getting this issue in the second PCI-E slot so 100% faulty PCI-E slot.