Riser question

I have a couple of my rigs acting weird they have been running fine for a while. (weeks) but recently two of them started going down and I did not change anything.

It is not hot here and they have been running through a lot hotter weather.

5x 380x
2000 watt PSU
usb risers
windows 10

5x 290x
2000 watt psu
usb riser
windows 10

I am using claymores miner. 15.2 drivers. 20 gb virtual ram ect

They boot up great start to mine everything is running cold then the whole computer just crashes. It might be time to rebrick them I have not done that in a while.

After maybe 30 second to 30 min the whole computer just crashes. Nothing in the log most of the time sometimes I get a couple of GPU failures. it acts like it is a power issue like the cards are not getting the power the need i have tried all the cables I am trying a new PSU now.


Now for the question. Do risers ever go bad where they work to start with then when under a load they give out?

The reason I am asking is every time I have had one go it they just will not let the computer see the GPU at all, but if they will let the computer see it then go out afterwards that could be what is causing my problems.