Are you using windows? Use linux if you want more than 4 GPUs. As an experiment remove one of the GPUs running on the x16 slot. Does the x1 slot card work when only running 4 GPU?
Note: I had the exact same problem utilizing a Gigabyte Z77X-D3H. I did at some point get the five cards to be identified; but, the network card failed to operate properly and I was unable to mine.
Yes im using windows 10 ! I bought a gigabyte ga-990fxa-ud3 and plugged the usb risers (1x to 16x adapter)
And Everything worked perfect
When i put it in pci-e adapter in pci-ex 1x slot it did not work and it burned my onboard network lan and my usb 3.0
It's already the 3rd card I try to use
And this time the network stopped working because I put the riser on the pci-ex 16x
This is the Riser Model
https://www.amazon.com/gp/product/B01CU1U2XG/ref=oh_aui_detailpage_o00_s01?ie=UTF8&psc=1Im try to put only two GPU´s ! First in 16x and second in 16x, and not work
what im need to do