I had issues with my thermal paste and decided to replace it on my original Xbox console. The graphics heatsink is difficult to remove.
Using iFixit repair guides, I dissassembled the Xbox, removed the CPU heatsink without much trouble, using a heavy duty spudger. The graphics heatsink was a different matter, this required me to insert 4 metal spudgers, (one on each corner of the heatsink, and simultaneously depress all 4 spudgers at once to remove it, using considerable force. None of the spudgers, or the motherboard, or the graphics processor under the heatsink were even slightly damaged!
There must be an easier way of removing the graphics processor heatsink to replace the thermal paste with a quality thermal grease to ensure adequate cooling! I was fortunate to be able to rely on my high tensile spudger set and many hours spent improving my digital dexterity and coordination to provide sufficient levering force to crack the thermal paste bonding the heatsink to the graphic processing chip. Unfortunately, I was so engrossed with this chore that I did not remember to photo this. Removing the old paste is simple with Arcticlean!