whe you have good quality risers - you have much less strain on the bus ...
Most of my risers are non powered because the asus rock board have 2 extra powerplugs on the mainboard(picture below). I have no problem to fit
6 cheap non powered china riser cables with this setup
the reason i dont use them is purely because there have been a LOT of issues with these boards and the onboard power connection ...
through various forums ( uncluding the asrock one - which doesnt have much to do with the mining arena any longer ) the boards have been brought up as being a way of warming your house by means of fire rather than hot air ... apparently that if the sockets and cables supply dont get the power they require for any reason - they ignite in the worse cases ... the least cases ( which is the common one ) is that they burnout your cards or the board itself ...
if yours are running well - then kudos mate
...i wont risk it ... not even for my little gigabyte 750ti oc lp cards ...
but thats the main reason - otherwise 'theoretically' they should run flawlessly ...
and with the 34 cable risers that i had to toss for faults - i refuse to use the cheap cable risers ... i suppose if its a couple that you have running - they wouldnt be exposed to the same heat / stress as in thefarm ... but i wont use those cables any more - only quality usb one ... if we were living close - id give you all the others that are laying here for free ...
...#crysx