There are special grooves in the copper base of the cooler for each of the heatpipes, which increases the contact surface and improves heat conductivity:

Unfortunately, the base of the cooler is of Thermalright’s typical quality: you can not only see the machine marks with a naked eye but even feel them to the touch:

The evenness of the base is also traditionally “good”, i.e. its middle part stands out:

As a result, the thermal compound imprint on the CPU heat-spreader turned out uneven:

As you may have guessed, the bent cooler base contacted the processor heat-spreader only in the center, however, despite this fact, Thermalright Ultima-90I turned out pretty efficient, unlike Noctua NH-U9B. Looks like even a small contact spot like that is enough to ensure proper cooling of a 45nm processor. However, I am sure I am not the only one who would like to know when Thermalright will finally start making even bases for their cooling solutions? Not to mention the polishing of the base, of course.