I was asked to take a look at a Dell XPS 15 L521x ultrabook because it was having video flicker problems. I originally took the approach of swapping out the thermal paste which helped a little, but the problem persisted. However, looking at the heatsink assembly, it was clear the problem wasn't the thermal paste, rather the heatpipe and heatsink is way too small for the Intel Core i7 and nVidia video processor. Remembering a similar issue with the HP Pavilion tx1000, the Dell XPS 15 L521x also had the heatpipe and parts of the heatfin covered in a black paint. I decided that it was time to scrub it off.
Before photo of the heatpipe and heatfin.
After photo of the heatpipe and heatfin. I scrubbed off the black paint using high isopropyl alcohol and a 800 grit sandpaper. A regular toothbrush had no effect on the paint. I had to use something a little more abrasive. The 800 grit sandpaper doesn't grind, it polishes. I use this particular sandpaper to polish down uneven heatsink surfaces. Even still, I couldn't get all the paint off.
