Given Noctua's track record, it's no surprise that their latest 1000g dual-tower is handling with ease a Xeon E5-2687W in passive mode. The 150W CPU never reaches more than 64°C at full load.
We don't condone such a sizzling hot processor in a fanless build, but low power i3s, i5s, and even i7s should be perfectly safe with the NH-D15.
Source: Hardwareluxx.de
