Some devices are still tuning so hashrate can be lower than expected
Hi, from two months ago till now this issue is started to appear  "Some devices are still tuning so hashrate can be lower than expected" .
Im running a SAPPHIRE NITRO+ Radeon RX 580 8GB on Win 10 with Nicehash Overclock 1150clock 2150mem tdp 90W with latest AMD drivers.
At the start this error appear "Some devices are still tuning so hashrate can be lower than expected" and after 15/20min it disappear but the pc is extremely sluggish and after 20min max Nanominer reboots, the hashrate is the same.
I have runned Nanominer always fine but now is impossible to run, i searched on the internet but not any relevant or releted problem i've found. Any help?