Boas... Não sei se isto ajuda, mas pelo menos ficas com uma ideia...
Removing the OEM Heatsink/Fan:
First disconnect the OEM Fan's power connection.
Disconnect Fan Power
Using a pair of needle-nose pliers, pull the OEM retaining pins straight up out of the mounting posts.
Remove OEM Heatsink Retaining Pins
Once the press-pins are removed, press out the two plastic posts from the rear of the card. (If necessary, compress the tips a bit - but the shape of the tips usually does that automatically when pressing down on them.) Note: Avoid using any sharp/metal tools that might slip and cause damage to the board.
Press Out the Two Retainers from Back of Board
Once the retainers are pressed out from the board, you can then remove the heatsink. Verax's instruction sheet suggests removing it by turning to break the thermal compound (which is almost a cement literally on this card), but I just lifted it off. Take care to not damage the GPU chip. Using a hair-dryer to warm up the heatsink may also help. The photo below shows the mating surface of the OEM heatsink - note the raised contact patch area (not flush).
Raised Contact Patch on OEM Heatsink
9800 Pro w/OEM Heatsink Removed
Alcohol is recommended to clean the GPU surface, but that wasn't nearly adequate to remove the OEM thermal cement from the GPU surface on this sample. Had I heated it up that may have helped, but the photo below was taken after about 15 minutes of cleaning attempts with Alcohol, including scraping with a plastic tool. (Do not use anything metal or harder than the GPU, which could chip or scratch the surface.)
Alcohol didn't fully remove the OEM Cement
Although I can't suggest you do so (it's *highly flammable* and a health hazard), I keep a can of Acetone (purchased at Lowe's) around. I avoided Nail Polish Remover which in some brands may also have oils. Acetone cleaned the GPU to a mirror finish. (The photo angle doesn't do the actual surface justice.)
Acetone Clean (Mirror Finish)
Espero ter ajudado...
Hazta!