Thanks for the reply.

By today's standard my whole system spec is slow to be honest.

But slow ram speed shouldn't cause this problems with powerplay. As I can run
the card fine with load or idle with kernel version 5.0.17. It seems to me the
new commits from AMD for kernel version 5.1 is to blame. But I can't say for
certain.

Interestingly enough if I use amdgpu.dpm=0 to disable dynamic power management
kernel version up to 5.1.6 works just fine except crappy performance when under
graphics load.

I was curious so checked out the commit log on amd-staging-drm-next branch. And
I see some reverts of powerplay related commits.

Link: https://cgit.freedesktop.org/~agd5f/linux/log/?h=amd-staging-drm-next

I am currently waiting for this to getting merged with master branch.