Success! I removed the cover and then the heat sink easily! I then applied a handsome amount of Arctic Silver 5 to the GPU, reassembled and reinstalled the card. GPUz sensor tab now reports 26-27c idle @ 750-780 RPM compared to 36c idle @ 750-780 RPM (20% Fan Speed) before applying the grease. I have yet to see the results after running Crysis on * maxed settings.