MSI Radeon 580 Armor memory automatically downclocking / fluctuating

Hi Everybody,

 

I recently bought an MSI Radeon 580 Armor 8Gb. I'm using it to mine, so the idea is to downclock the GPU and overclock the memory. Some parameters I'm using with claymore are:

 

-cclock 1135 -cvddc 950 -mclock 2150

 

The problem I'm having is that when overclocking the memory over the 2000 Mhz (i.e. 2150 Mhz), the clock keeps fluctuating from 2150 to 1000 every three seconds. Even the overclock was only 2001 MHz, it would behave the same way. Check the graph:

 

 

 

I'v tried different drivers:

- 17.7.2

- 17.8.2

- Blockchain version

- Several old drivers

 

All clean installed (using DDU). I don't know what else to try.

By the way, the power efficiency button to turn this feature off, doesn't appear on the AMD setting app.

 

Any idea guys?

 

Thanks in advanced.