HIS Radeon 6870 IceQ keeps crashing

I have a Radeon 6870 by Powercolor (stock cooler) for a while, and I've decided to get another one to put it into crossfire (didn't have enough cash to upgrade to r9 card). However, the card that I bought (HIS 6870 IceQ Turbo X) keeps crashing in game and I don't know why. The Powercolor one works fine except it is heating up a lot (like 100+ degrees) so it is in service for a clean-up and new thermal paste (couldn't open it myself because of warranty issues). But even when the Powercolor one is overheating it is working fine, while the HIS one keeps crashing my PC.

 

My PC specs are:

 

Gigabyte 990FXA-UD3 mobo

HIS Radeon 6870 IceQ Turbo X gpu at stock

Corsair Vengeance 2x4gb ram at 2133 Mhz

AMD FX-8350 Cpu at stock

Samsung SSD 840 EVO 120gb

Raidmax 835watt RX-835AP 80plus bronze PSU

Windows 8.1 x64 os

 

Just to be clear, the problem isn't with the crossfire, the card itself is crashing, while the other one is ok. No error messages are showing after booting up and the temps are around 40 degrees Celsius idle and 60 in-game (until it crashes). Uniengine Heaven benchmark is also crashing it. I've uninstalled the drivers with guru3d tool and still nothing. Just freezes in-game and sends my monitor in power saving mode and in the background is some buzzing sounds. Sometimes it doesn't send my monitor in power saving mode but it crashes the game and recovers the driver, but the reinstall doesn't help it. And some games like NBA 2k14, League of Legends, CS:GO are working perfectly with it but in TERA: Rising, Far Cry 3 and other more demanding games it crashes. Thx for the help!

It's possible you just have a bad card. I'd think it would be your power supply being of low quality, but you said your powercooler one works fine so that's probably not the issue.

Agree - HIS card is faulty.

Damn exactly what I thought it was... And my warranty expired. Now can you tell me is it possible to change the cooler unit from the his one to the power color one?

When I started to have issues with my HIS IceQ Turbo 6790 the rate of occurances accelerated quickly. However this card was quite well built and over clocked very well, before that point. (Just maxed the speed sliders, no voltage changed). Overall I would not reccomend as a used card.

Back to your specific issues. I would say it sounds like the cards temperature sensor has come unsettled, seeing as software is rarely ever the issue, on commercial devices, in my experience. I'd say try a rattle test, just gently shake it and listen for a rattling noise. If none occurs try pressing the heatsync into the chipset with a clean elastic band during operation, see if that fixes the issue. It could be a inaccurate reading of the temperature, by the cards firmware, caused by poor contact of the thermal proble to the heatsync or GPU chip.

::Edited because of android autocorrect.::