Upload your bios, I'll mod it for you and PM it back.
I'd like do it in several steps to make changes easier to track, although most 970's work very similar on a bios level.
-- Some info to help clear things up for future readers --
The watts you set in bios are not TELLING the card to draw that much, nor will the card draw endlessly until it reaches the value! In many cases values over 500 must be used to prevent throttling, but a 970 cannot physically draw anywhere NEAR that much obviously.
With the 900 series you can disable all power limits and throttling in the bios. so it will hold clocks steady until 100c. Obviously your ability to hold those clocks goes down the higher the temperature. For example, <76c 1520MHz is stable, 77-82c 1507MHz is stable, 83-86c 1493MHz is stable and so on. (Silicon lottery will put you between 1480-1533MHz). Official safe temperature is 95c, although you won't risk killing or damaging it unless you're pumping upwards of 1.4v into it while running somewhere over 105c for "a length of time".
It will TDR far before that. Even a bad thermal paste application where it shoots to 103c instantly will just TDR due to instability.
It's probably safer to run with throttling disabled haha.
As long as you've gotten rid of the stock thermal paste or "thermal cement" as I like to call it, you'll have no issue keeping below 82c even with bad case airflow. Normal load usage (not Furmark/OCCT) will probably have you mid-low 70's at most.
The fan RPMs are locked as well. Some may only spin up another 200RPMs. They're usually designed for 3200-3800rpm and limited for noise performance in reviews. However in one case I unlocked fans on a 970 and they just kept going, reaching an ear shattering 5200rpm!
(It sounded like a vacuum cleaner haha!)
Anyway, this post is too long.