So I got an RX470 4GB Gigabyte G1 Gaming for my sons DELL (it just fit) ..
https://www.gigabyte.com/nz/Graphics-Card/GV-RX470G1-GAMING-4GD#kf

It was ok for a few days, but the fans were really loud and when I spun by hand they felt horrible.
I got new fans from AliExpress and they work well, no noise and solid RPM etc but since I put them on it crashes at 61deg. I put the old fans back but it still crashes at 61deg.  

I reflashed vBIOS from Gigabyte Website but didnt help.

If I use AMD settings or MSI afterburner to push fans to about 60% it stays under 61deg and will not crash, can run FurMark for over 2 hours, but drop fans back to 40% or leave them on auto (start at 33% and then got to 50%) and temp hits 61deg and it crashes.

I think the silicon must be OK, RAM passed all the tests I could find .. I'm assuming somewhere internally when it hits 61deg it thinks its hit 95 and shuts down for safety.

Anyone seen this before ?
Could swapping the fans I have done some damage ?

Got any ideas on a solution as the noise from running fans this fast is getting a bit annoying now.