All 5000 & 6000 Series GPU cards have a Maximum Operating Temperature of 110c. So if you GPU card "Hot Spot" reaches 100c it is still within its engineered Temperature range.
But if it starts reaching or passing 110c then you need to troubleshoot to find out why it is running so hot.
Awhile back I read that the 5000 & 6000 series GPU average temperature for Hot Spots is around mid-80c to low 90c.
But if you can keep below 90c the better.