Make sure you have the drivers 18.12.2 installed then follow these steps:
1- go to Wattman
2- go to Fan & Temperature section
3- change Speed/Temperature option to MANUAL
4- move/drag the yellow points on PWM% Temperature Chart as follow
5- the last point at 56'C,95%
6- the 4th point at 51'C,73%
7- the 3rd point at 46'C,55%
8- the 2nd point at 41'C,40%
9- the 1st point at 36'C,35%
10- press Apply button and save the profile
Your card will stay colder and you might want to lower the gpu clock, in GPU section, adjust the orange vertical lines.
You can slide down those orage buttons, decrease STATE 5 STATE 6 STATE 7 with 70 Mhz or 50 Mhz.
Press Apply and save your profile.
And if you dont mind, you can remove the pc case lateral panel, but only if you dont have a good air flow inside your case. If the hot air isn't eliminated quickly, the whole system becomes hot.