Suddenly graphics card not working well

[SuperGuy]

i have a gtx 970 and when i play overwatch on low settings i get a smooth 180-200 fps
suddenly i got this error with my graphics card and after fixing it by cleaning the pc the game isnt running as well
it starts off with 200~ fps but 2 minutes in game and its going down to 100 fps
this is happening with other games as well
Do you have any idea on what i should do?

 

[vapour]

What error is it? Driver? If so, delete the old GPU driver and reinstall. Doesn't look like a hardware issue.

 

[SuperGuy]

What error is it? Driver? If so, delete the old GPU driver and reinstall. Doesn't look like a hardware issue.

im not getting and error the problem is the the games are not running as well as they used to

 

[vapour]

I meant error in your statement "suddenly i got this error with my graphics card and after fixing it by cleaning the pc the game isnt running as well"

 

[SuperGuy]

I meant error in your statement "suddenly i got this error with my graphics card and after fixing it by cleaning the pc the game isnt running as well"

the error was different for every game but for overwatch the error said "your rendering device has been lost"
and i am not overcloocking just to be clear

 

[vapour]

Try this:

https://www.youtube.com/watch?v=FMzNoQlj9NI

 

[SuperGuy]

Try this:

https://www.youtube.com/watch?v=FMzNoQlj9NI

after playing 2 games i cna say that i still suck at overwatch
but at least i suck at a constant 200 fps
thanks for the help