Question GPU performance dropping with time

[Teknoman2]

When i turn on the PC (or after a restart) and start BDO, the metrics show that the GPU is drawing on average 100W and the fps are on average 80. After a few hours of having the PC on playing the game, the power draw of the card and the fps start slowly dropping until it gets unplayable and i have to restart the PC. Could this be because of the age of the card or the PSU (both about 5 years old)? Or is it some windows or driver setting that causes it?
you can see the PC bellow.

 

[Archaic59]

When i turn on the PC (or after a restart) and start BDO, the metrics show that the GPU is drawing on average 100W and the fps are on average 80. After a few hours of having the PC on playing the game, the power draw of the card and the fps start slowly dropping until it gets unplayable and i have to restart the PC. Could this be because of the age of the card or the PSU (both about 5 years old)? Or is it some windows or driver setting that causes it?
you can see the PC bellow.

I'd be looking at CPU and GPU temps to see if heat is building up over time, which can slow things down.

 

[Teknoman2]

The CPU never goes above 60C and most of the time it sits on the low 50s while gaming. The GPU on the other hand hits 75C+ at first but as the power draw starts dropping so does the temperature.