We've already written about Thermalright's HR-02 CPU cooling, one of the pretty hefty solutions claiming to pack enough punch to passively cool a Core i7. As sceptical as we are, we've had our doubts as well, but Thermalright has proven to be right on the money. In fact, semi-passive operation will help the HR-02 in cooling a Core i7 930 at 2.8GHz and even a Core i7 965 Extreme at 3.2GHz.
HR-02 has a large dissipation surface making it easy for the passive cooler to release heat. Like any other passive cooling solution, HR-02 too requires at least some basic airflow within the case. HR-02 performance will naturally be improved if you strap it with a fan, but since the HR-02 was designed to passively cool Core i7 CPUs at reference voltages and clocks, a decent airflow within the case will do the trick.