Readers who tenaciously seek silence in their PC will probably recognize the Thermalright Ultra 120. It is not exactly the same heatsink, but it is similar in appearance to the HR-01 fanless cooler introduced by Thermalright in late 2005. That cooler shipped for AMD only, as we were still in the hot Intel Prescott days. Adapters were introduced later to allow HR-01 to mount on newer sockets, and HR-01 is still in the Thermalright product line as a fanless cooler.

However, there is no way to even mount a fan on the early versions of HR-01, so its appeal was limited to users seeking silence at around stock speeds. Overclockers really had little use for the HR-01. Thermalright recognized that a cooler designed to perform well with no fan could be very attractive to overclockers if there were some means of active cooling, and so the Ultra 120 was born.

The Thermalright Ultra 120 refines the shape of the HR-01 and adds the ability to mount a 120mm fan to the heatsink tower. If you look closely you can see that the cooling fin edges are turned up on one end and turned down at the other end of the same fin. This creates airflow patterns that are refined in subtle ways from the more common flat fins. Unlike the HR-01 the Ultra 120 is designed to operate with a 120mm fan. The heritage, however, is the fanless HR-01 design, and we will also evaluate the Thermalright Ultra 120 as a fanless design.