Sudden increase in GPU Temperature, sudden drop of FPS

[asteris_]

Greetings. After I recently installed GPU cooler http://www.arctic.ac/eu_en/accelero-l2-plus.html in HD 7850 (due to broken fan) soon after stressing the card temperature rises very high and FPS drop instantly to 10 along with the temperature.
What I did while installing the cooler was removing the pre-applied thermal gel in the heat-sink and replacing with the thermal glue of the box (Glue TG-003).

So the question rises, to save the GPU. Either 1 the thermal glue is not supposed to be used in the GPU heatsink, and that's why the T rises very quickly so I must use a different kind of gel or 2 the cooler does not efficiently cools down the GPU due to its small size.
Please any kind of advice is appreciable, I can't afford to buy another card.
Thanks in advance.

 

[Goodfeller]

It is probably the second option; the cooler might not be enough. I had the same problem. When the GPU reaches high temperature it goes crazy. I'd say, replace the cooling.

 

[asteris_]

It is probably the second option; the cooler might not be enough. I had the same problem. When the GPU reaches high temperature it goes crazy. I'd say, replace the cooling.

So the cooler has to fully cover all the GPU? If that's the case why are they selling it in the first place?
Also does this explain the really sudden increase in T?

 

[Goodfeller]

Some coolers are just crappy. It may be, that the cooler is somehow broken or the heat sink isn't fully attached to the gpu processor.