Passive 1U rackmount CPU cooler from Dynatron for Intel LGA 2011 (Socket R) Sandy Bridge server processors.

Constructed from copper for optimal heat transfer and sporting vapor chamber technology, the R15 supports a CPU with maximum TDP rating of 150W. Thermal compound is pre-printed with Shin-Etsu G751; no additional thermal compound is required.The R15 passive heatsink is designed to be used in conjunction with an active cooling system; the 1U case must have active cooling, e.g., fans.

What is a Vapor Chamber and how does that help me? A vapor chamber is, in essence, a flattened heatpipe in direct contact to the CPU surface that transfers and dissipates heat more efficientlythan a traditional heatsink can manage. The vapor chamber is air tight, containing a coolant, and operates through a continuous cycle of evaporative cooling. What this provides you with is more effective cooling and CPU thermal protection with no additional bulk.