Issue resolved, it was drivers.  Apparantly because I had unplugged them from the board it had applied the default drivers.  New drivers are on and back to 24.

I checked all the drivers and they are the same I was using at 24 h/s.  To your link as well is says or use the crimson blockchain driver which is what I am using.

If that were the case wouldn't his linux rig have the same constraint. However when running linux he gets the usual 24 h/s.  If he switches the same machine to nicehash or windows claymore 15 h/s.  Same internet connection.

I have 2 rigs, 18 gpus, mixed AMD 580/480 and Nvidia 1060 and 180ti.  For the most part the AMD are one one and the Nvidia on the other.  I recently moved both to cooler, location for the summer.  My landlord who is renting me a shelf is an IT Networking guy so his shop has a lot of stuff in it, servers etc., he also has one miner.  For the move I unplugged all the gpus and boxed them, taking careful note to the slot they were plugged in.  At the new site I set them up exactly the same.  The AMD rig fired up no problem.  The Nvidia rig had a power supply go out in the process which caused a repair but added a new one and it fired up.  I verified all the same drivers were installed as they had been before.  I started mining.  All Gpus responded and mined.  However after watching I noticed that the 580's are all showing a hashrate of 15 h/s, they typically do about 24.  I should add that the Nvidia machine has two 580s on it and they too are running at 15 h/s.  So all my 580/480s over two rigs are down 40%.  My 1060s also appear to be down about 25%.  My landlord assures me the speed coming in is ample. 

As a kicker I mentioned he has one rig.  He is on a different switch than me.  He has the same problem with his AMD cards on his rig however he switched to Linux to mine and it appears to have worked which does argue for the speed coming in is enough but why this problem when I mine on Nicehash or Claymore?

I would love to know why suddenly with no changes to the software or hardware this has happened by plugging in a different internet line.

I know the easy answer is switch to linux but I would also like to know why this happened.

Any ideas community?  Any one have the same problem.  It is so specific, they are all from 24 to 15 across the board on AMD and the Nvidia all went from 20 to 15, the 1080s are at 32 which is consistent with what they should be.

Thanks,
I realized as soon as I post that this is bitcoin mining only.

I have 2 rigs running.  Due to heat I recently moved them from my home to a workshop.  I disconnected all the GPUs for this move but made sure to document which slots they came from and put them back in the same place. I Plugged them in at the new location and got everything up and running.  I didn't make any software changes.  I sat them down, plugged it all back in and turned it on,  I had to rebenchmark one of them but the other was fine.  However all of my RX 580s and 480s (on two separate machines) went from hashing at 24 down to 15.  The NVIDEA cards do not seem to have the problem.  Any ideas? I would point to the internet connection but the connection is fine.  Plenty of juice and there is a third machine on site that has the same problem but he turned it over to linux and it is back at 24.  What is going on here?  I have racked my brain and can't come up with anything.

I have 2 rigs running.  Due to heat I recently moved them from my home to a workshop.  I disconnected all the GPUs for this move but made sure to document which slots they came from and put them back in the same place. I Plugged them in at the new location and got everything up and running.  I didn't make any software changes.  I sat them down, plugged it all back in and turned it on,  I had to rebenchmark one of them but the other was fine.  However all of my RX 580s and 480s (on two seperate machines) went from hashing at 24 down to 15.  The NVIDEA cards do not seem to have the problem.  Any ideas?  I would point to the internet connection but the connection is fine.  Plenty of juice and there is a third machine on site that has the same problem but he turned it over to linux and it is back at 24.  What is going on here?  I have racked my brain and can't come up with anything.