There is a great difference between "true" Dell Precision series (e.g. the 7000 series) and those Dell Precision which are just rebranded Dell XPS and which are marketed as thin and light laptops.
The Dell Precision 7xxx have excellent heat management. I have a 6-year old Dell Precision 7510 mobile workstation, in which the CPU can dissipate in the steady state 60 W for hours (even if its nominal TDP is only 45 W), while the NVIDIA Quadro GPU also dissipates around 100 W at the same time, and this without overheating and without excessive noise.
Obviously, this is a rather thick and heavy laptop, not an ultrabook.
