I've been mining since 2.4, now on 2.7b, on a single Vega 56, W10, latest drivers, and it's been mostly fine. I've only experienced one recurring problem where mining stops (driver crash AFAIK) then restart and hangs at detecting cards for 60-80 minutes before resuming mining. Before 2.7b, my wattman overclock settings were reset to default, now with 2.7b I get to keep my settings which is much better already.
Crash
17590:09:57:09.365: eths Eth: Received: {"id":6,"jsonrpc":"2.0","result":true}
17590:09:57:11.118: wdog GPU1 not responding
17590:09:57:11.118: wdog Thread(s) not responding. Restarting.
17590:09:57:13.351: eths Eth: Received: {"id":0,"jsonrpc":"2.0","result":["0x67eee33b64b12a758aae121933ceda21975d7f6465e6cd9e2df2564ab35ec43f","0x1261dfe17d0bf58cb2861ae84734488b1463d282b7ee88ccfa18b7a92a7b77f7","0x0112e0be826d694b2e62d01511f12a6061fbaec8bc02357593e70e52ba","0x4ee526"]}
17590:09:57:13.351: eths Eth: New job #67eee33b from eu1.ethermine.org:4444; diff: 4000MH
17590:09:57:14.343: main Eth speed: 0.000 MH/s, shares: 440/0/0, time: 10:42
First auto restart, failed to generate DAG (GPU might just be down/driver still hasn't recovered fully)
17590:09:59:10.755: main Phoneix Miner 2.7b Windows/msvc - Release
17590:09:59:10.755: main Cmd line: -pool eu1.ethermine.org:4444 -pool2 us1.ethermine.org:4444 -wal xxx.xxx -cdm 0 -amd -fanmin 10 -fanmax 20 -tmax 65 -powlim 50 -cclock 997 -cvddc 935 -mclock 1125 -mvddc 950 -minRigSpeed 39
17590:09:59:10.844: main Available GPUs for mining:
17590:09:59:10.844: main GPU1: Radeon RX Vega (pcie 3), OpenCL 2.0, 8 GB VRAM, 56 CUs
17590:09:59:10.855: main ADL library initialized
[...]
17590:09:59:11.260: GPU1 GPU1: Starting up... (0)
17590:09:59:11.260: GPU1 Eth: Generating light cache for epoch #172
17590:09:59:11.370: main GPU1: 32C 13%
17590:09:59:16.214: main Eth speed: 0.000 MH/s, shares: 0/0/0, time: 0:00
17590:09:59:19.103: eths Eth: Received:
[...]
17590:10:00:42.820: wdog GPU1 not responding
17590:10:00:42.820: wdog Thread(s) not responding. Restarting.
17590:10:00:46.823: main Eth speed: 0.000 MH/s, shares: 0/0/0, time: 0:01
Second auto restart, where it hangs for an hour+
17590:10:00:53.931: main Phoneix Miner 2.7b Windows/msvc - Release
17590:10:00:53.931: main Cmd line: -pool eu1.ethermine.org:4444 -pool2 us1.ethermine.org:4444 -wal xxx.xxx -cdm 0 -amd -fanmin 10 -fanmax 20 -tmax 65 -powlim 50 -cclock 997 -cvddc 935 -mclock 1125 -mvddc 950 -minRigSpeed 39
17590:11:12:48.891: main Available GPUs for mining:
17590:11:12:48.891: main GPU1: Radeon RX Vega (pcie 3), OpenCL 2.0, 8 GB VRAM, 56 CUs
17590:11:12:49.049: main ADL library initialized
17590:11:12:49.367: main Eth: the pool list contains 4 pools
17590:11:12:49.367: main Eth: primary pool: eu1.ethermine.org:4444
17590:11:12:49.367: main Starting GPU mining
I've had 60/70 hours longs runs without issue, even while changing clock settings and playing games etc.
I'll gladly help with more logs and more details, feel free to ask