Samurai, I got my Arctic Accelero Xtreme 7970 and installed it.
The mounting system is terrible.
They provided cheap plastic ring spacers for the screw holes that you're supposed to hold on with paper double sided tape that doesn't even work. So, I skipped using the spacers completely.
The backplate for the top of the card has EVA foam that sits between the metal backplate and the card (above the chip). So I tightened all 4 screws down to secure the heatsink to the card. However, in the manual they recommend you only turn each screw 2 rotations to secure the cooler to the card. The problem with this is that the thing is so heavy that it won't be tight enough and eventually the weight of the heatsink will seperate the heat plate from the GPU chip itself. The only thing making them keep contact and cool the card was the thermal paste. Eventually the seal from the thermal paste popped and then the plate came right off the chip, which made my card crash doing anything in 3D mode with temps over 100C (triggering the anti heat protection and shutting the card off, making my monitor get no signal).
So I tightened the screws down even more, but not quite to the point where the backplate was touching the back of the card. It seemed fine for a day but now again I had issues with the card crashing in 3D mode. So I open my case up and pull down on the heatsink and sure enough, it's not making full contact with the VGA chip.
I just redid the thermal paste, and this time I tightened the backplate down with screws until the screws were all the way in and the metal backplate is touching the back of the card in some spots. The EVA foam is also heavily compressed all the way against the components behind the VGA chip.
Wondering if there's any issue with a non insulated metal plate making contact with the back of the VGA board. I might want to tighten this thing even further just to prevent it coming loose at all over time from the weight of the heatsink. Though it seems to be fine now.
Here's a video, in Egyptian unfortunately showing the install on my card. Should still give you an idea of the process. Keep in mind I didn't use the little plastic spacers, and if you did I think the heat plate would eventually lose contact with the chip: http://www.youtube.com/watch?v=QtVJ5Pah5YI
Here's a thread I found about this cooler and my card. http://www.overclockers.com/forums/showthread.php?t=725149