Try this one
https://drive.google.com/open?id=1buFOCC3j87tw5U5809KLqxQUQPflHuiQ
It's 1200/2000, not so hard on undervolting, it seems not to have those strange clock issues in Windows.
It gives me 29+ MH/s on ETH.
As I said I'm not unhappy with performance, but power consumption optimization.
The card is more than stable @ 1100 core and 900 mv or less. No problem in Linux, but Windows drivers somehow mess up with clocks with this undervolting.
https://drive.google.com/open?id=1buFOCC3j87tw5U5809KLqxQUQPflHuiQ
It's 1200/2000, not so hard on undervolting, it seems not to have those strange clock issues in Windows.
It gives me 29+ MH/s on ETH.
As I said I'm not unhappy with performance, but power consumption optimization.
The card is more than stable @ 1100 core and 900 mv or less. No problem in Linux, but Windows drivers somehow mess up with clocks with this undervolting.
Thanks for sharing, finally some hope
Im able to get 28-29 mhs an latest adrenaline driver, will test it a bit more and had also a funny experience with it on blockchain driver where the flashed card where mining 75-101 Mhs (single!!!) 
would be nice but unreal.... I will test it more and will give you my feedback
Thank you very much for your help.