I dont overclocked memory. The default value is set.
To be honest, I do not believe you ...
This error in 99% cases = bad memory timings, overclocked memory ... or broken video ram chips
:-), Consciously, I assure you that no.
I can give you more data, the problem is happening to me with Arch Linux with kernel 4.16 and mesa 18.04.
But
it works properly in Ubuntu 16.04 with kernel 4.13 and mesa 17.3.
So, I do not know if the problem can be something derived from the kernel, mesa and xorg.