Same thing, plugged a 1x to 16x adaptor into it and led it up to the card. not enough room to plug the card directly into the slot. Since this rig is only being used for mining there is little to no loss of performance in a setup like this. I actually made a video talking about it and showing the setup here:
But theres only five x1 slots
1x can go into a 16x
Oh. Im stupid
Haha no problem man. These aren't exactly normal machines.
If you are still curious about any of it let me know, also that video I posted in the comments covers the build process :)
Whats your hash rate?