I have a RIG with a RX VEGA 56 and other 7 GPU (RX470 and RX480), when I run all toghether with Cryptonigh I have jus 800 H/s on VEGA, but in other PC just with 1 GPU RX VEGA the hasrate is 1950 H/s why this different behaviour ?
You have to tweak your vega in order to get such values
use this guide
https://www.reddit.com/r/MoneroMining/comments/74hjqn/monero_and_vega_the_definitive_guide/
Once done you would be able to reach 1900 h/s per vega gpu
I did and it works perfectly alone on other PC but when i put in a RIG with other RX GPU the hashrate is bad !!!
My MB is an Asrock H110 BTC+ with 13 PCI-e slot
you've said what the problem is many times, yet you do not pay any attention to what the solution is, PUT THEM IN DIFFERENT RIGS!
clearly rx 400 and prolly 500 series gpus do not work well with the vega installed in the same system. solution make a vega rig and a rx 470/480 rig.