I wanted to share my experience with changing the thermal paste in my 15" Macbook Pro Retina. Using iStat Menus (currently 4.03) I've been closely monitoring my temps over the past few months. My "CPU Die - Digital" temp idles at around 50 C. This is the steady state temp, after a couple of hours, when there is little or no activity. When I use any app which pushes the CPU utilization to 100%+ my temp will go to around 102 C with the expected increase in fan RPM (around 3600 RPM). Given that the ivy bridge core is designed with a max temp of 105 C I decided to see if I could improve the temps by changing the thermal paste. Picture 1 shows the screen capture of my typical idle temp. Picture 2 and 3 shows the thermal paste application by Apple. After removing the heatsink I cleaned the factory paste off the die and heatsink with ArtiClean. I applied a thin layer of Artic MX-4 using the controversial "spreading" method (picture 5). Personally I don't believe that the application technique makes that much of a difference. My new thermal temps are now around 42 - 44 C at idle (compared to 50). The biggest difference I see is under load. With CPU utilization maxed out to 100%+ my temps are now stable around 80 C with the fan RPM around 2300. This is using the Macbook in the same ambient room temp where I had previously had temps go to 102 C). Quite honestly I don't think that the temp difference is due to just one factor. There are likely to be multiple things which contributed to the higher temps of the factory paste: 1) As expected they used too much paste. This alone isn't the going to kill the temps since much of the paste just get squeezed out by the pressure of the heatsink. However... 2) The screws on my heatsink were not tightened properly. They were too loose. This contributes to a less than perfect mating between the heatsink and die 3) The quality of the thermal paste probably made a difference. If you read all the benchmarks on the Internet you see that the different pastes have a different performance. However, they are generally close. I believe that all three factors above contributed to higher temps from the factory. Regardless, I'm satisfied with the new thermals as my 3D rendering apps no longer seem to be pushing my Macbook to the edge. BTW, changing the paste is pretty easy. You can reference iFixit but basically you just remove the bottom plate and you have access to the heatsink (don't forget to disconnect the battery). Just unscrew the standard torx screws securing the heatsink and you're all set. I'm sure someone will bring up the warranty but quite frankly I don't care what Apple thinks I should or should not be doing to my own $4000 laptop.