Question GPU underperforming

[octans.sigma2]

Hey , so i have this problem for about 3-4 months where when i play games my gpu has less power than cpu which causes fps to drop about 50% on every game i play
the gpu is Asrock rx580 8gb Gaming D ( bought about a year ago).

PSU : Corsair RM750x (bought today)
CPU : r7 2600 ( bought about a year ago)
RAM : 8gb 3200mhz ( bought about a year ago)
MOBO: gigabyte b450 s2h ( bought about a year ago)

 

[WildCard999]

The memory....single stick or 2x4gb kit? Is (A)XMP enabled in the motherboard BIOS?