Thank you for your reply!
I have tried with different risers.
Different PSU
Connect directly to MB
Setup to mine via NiceHash on Windows 10 - works fine
I bought it used but I have never myself touch vbios or OC settings
Changed MB ASCM settings
None of the above worked.
Hardware:
Motherboard
DH67BL Intel Corporation (BLH6710H.86A.0076.2010.1115.1959 11/15/2010)
CPU
8 × Intel® Core™ i7-2600 CPU @ 3.40GHz
Disk Model
ATA KINGSTON SNV425S 128GB
16 GB Kingston RAM
2x GeForce 1660Ti
what are your ALL oc values that u have on that 590?
Same problem. My amd Rx 590 mining well on Windows, but when try do this on hiveos miner goes offline after about minute.
what ? BIOSMod
my RX 590 in max 29,8MHs
Hello guys, I have same problem, hive can’t detected rx590 GME XFX, I try install any version of hive os beta or stable old or new and try push any driver from amd to hive but still Rx 580 detected by this stupid! 
With bios mod on NiceHash os (Linux) rx590 correct recognized and work with 32 MHS but I don’t like NiceHash buz very unstable,
But try with bios mod in hive and I can give this results, not enough but good for now , I hope hive support team or someone fix this problem
I have the same problem I bought a used 590 saphire and although it detects it, it does not start mining. restarts or cycles after the others started the job (rx 580 and 5600)
I changed my Motherboard and then it recognized my Rx590.
I have tested my RX590 8GB hashing stable 33.17mh
CORE: 1250
DPM: 3
VDD: 900
VDDCI : 0
MVDD: 0
MEM: 2200
MDPM: 1
This is achievable with flashed BIOS on Polaris BIOS editor
You need command on advanced config to boost memory on AMD cards:
amdmemtweak --REF 20 ( Samsung , Elpida )
amdmemtweak --REF 30 ( Micron, Hynix )
