Extended period of time was just 1 1/2 days.
The fan still seems to be working --
And is 84C on the shaders that bad? I thought they were good up to 90C?
Its not wise, doesn't necessarily mean it will fail, but the closer to the limit the closer to failure.
Would you walk along the side of a cliff for 1.5 days because normally you can do that without falling?
I would suggest sending it back to wherever you got it if uninstalling doesn't work.
I sent mine back to newegg asking for a replacement, they sent a full refund instead.
When you get a new card, use a more informative tool like HWINFO to view full temp stats about the card.
Down near 52.. the shaders show up as 55. That gap gets larger the hotter the gpu. Afterburner will only show the 52.http://www.hwinfo.com/download32.html