GPU Fans speed up -> clocks drop down.

[H_Four]

Hi everyone.

All of a sudden my graphic card started behaving weirdly.
It's Radeon HD7870 Twin Frzr 3
Procedure:
1) boot up pc
2) start up a game (any game. doesn't matter. can be furmark also)
3) immediately the fans are going up to 100%
4) after 3-10 seconds the game/program crashes to desktop
5) fans slow down to normal idle, cold gpu value ~30%
6) Core Click and and Memory Clock go down to 150MHz.

In order to get it fully running again I have to either reboot a PC or turn off/on via device manager.

-----
tried:
1) reinstalling amd drivers
2) reinstalling amd drivers using guru3d uninstaller
3) disconnected everything on the MOBO to make sure all connections are OK

Did you guys ever see such a problem? What can be the root cause? How can I go around it?

EDIT:
running furmark with GPU-Z open I get this:
http://imgur.com/a/pPlda (temp is max)
This is super strange since the fans are working properly, and before running furmark the GPU was at 37deg. It has risen from 3deg to 10)deg in about 2 seconds.
What?

 

[goku1234567890]

Hello there, how are you? Hope you are having a nice day. Can i ask you when did you buy this card?

 

[RSxx]

This sounds very much like a thermal issue. Monitor the temp's.
Clean your Cooler and if you still have issues redo thermal paste.

 

[nzalog]

Agreed with everyone this is most likely a thermal paste problem or the heatsink is not properly installed. You're temps should never reach 100C instantly like that unless the cooler isn't working. Also I doubt if the cooler was working that it would ever get close to 100C.

 

[H_Four]

@goku - it's an old card. I have it for like 4 years now or sth. pretty much since release. Yes I know it's old.

@RSxx I already cleaned everything. Although the thermal paste seems super dry now.
But then again, would it got to 100deg so quickly? Also - yes the GPU-Z shows the temp to be 100deg, but FurMark itself shows 60deg.

EDIT:
@nzalog - yea I know it looks that way, but the fans are working properly. Only thing that it might be is the dry thermal paste?

 

[nzalog]

EDIT:
@nzalog - yea I know it looks that way, but the fans are working properly. Only thing that it might be is the dry thermal paste?

So definitely replace the paste, dry paste can work sometimes depending on what it's made from but if you've opened it and then put it back with the dry paste that's even worse. The other important thing is make sure nothing is interfering with getting the heatsink to have complete contact with the core and that there isn't some gap.

 

[junkeymonkey]

never know a old cards fan may report speed errors or be bad incorrect . I had a 7850 this way over time .

pulled a fan out of another bad card and stuck it in the 7850 and all was back to normal so it had to be something in the fan sensor or motor ?

showed ''crazy'' rpm speeds and cooling was off and on like the software like gpu z or what ever showed the fan was at 40% speed but the fan was just spinning at a low rpm for that %. and at times may not of beem reving up to match gpu temps correctly ?

but the fan I pulled from a older 6850 worke as expected and temps were back to normal and maybe 76c at max

good luck

 

[nzalog]

But the fan speed does not matter if the core can't dissipate it's heat to the heatsink (which is being cooled by the fans). I bet his heatsink is barely even warm while his core is 100C.

 

[H_Four]

Yes, the heatsink is cold. completely. but then again, after running FurMark I shut down the PC disassembled the GPU and touched the core and it was also cold.
But OK, the time it took me to disassemble the GPU was a few minutes. Could easily cool down I guess.

 

[nzalog]

What ever happened, did you end up get it working correctly?

 

[H_Four]

Not yet, the shops were closed already last night, I'll buy the thermal paste today and try.

 

[H_Four]

[delete, mistake]

 

[H_Four]

What ever happened, did you end up get it working correctly?

Indeed it looks like the paste was the problem, now when I cleaned it and applied new paste all seems to be normal! Thanks!