The new all copper XP-90c heatsink from Thermalright provides excellent performance in a compact size that will fit virtually all motherboards.

Thermalright continues to be a highly respected name among computer enthusiasts seeking high-performance cooling solutions.  The Thermalright XP-120 that we reviewed back in October 2004 is one of the best performing heatsinks on the market.  However, because of its large size, the XP-120 is not compatible with all motherboard configurations.  The new XP-90c heatsink is an all copper version of the popular XP-90 (copper base/aluminum fins) that addresses the size problem but still provides outstanding thermal performance.


The Thermalright XP-90c is designed to use a single 92mm fan and incorporates four heat pipes to transfer heat out of the copper base into an array of thin copper fins.  The XP-90c’s universal mount works with both Intel P4 (socket 478) and AMD K8 (socket 754/939/940) platforms.  A P4-LGA775 mounting bracket can be purchased separately.


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The main features of the XP-90c are the ability to provide excellent cooling along with quiet performance in a small package that will fit virtually all motherboards.  While not as large as the XP-120, the wingspan of the XP-90c also provides extra cooling to other components located around the CPU socket area, like the NB, RAM modules and MOSFET voltage regulators.


Main Features:


  • Compatibility with virtually all motherboards
  • All copper construction for optimum heat transfer
  • Ability to directly mount a 92mm, quiet fan
  • Four heat pipes to help provide maximum heat dissipation
  • Large fan area provides extra cooling to the motherboard
  • Universal mount, easy to install



  • Construction: Forged copper base, copper heat pipes, and copper fins
  • Dimensions: 116L x 96W x 75H (mm)
  • Weight: 690g (without fan)
  • Recommended fan: 92mm Panaflo medium speed (FBL09A12M)
  • Universal mounting hardware for P4 and K8 platforms


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 Heat Pipe Technology


The XP-90c heatsink uses four copper heat pipes to transport heat from the heatsink base up to the large surface area provided by the copper fins.  A heat pipe is a highly efficient conductor of heat.  A properly constructed heat pipe has a very low thermal resistance, which is roughly independent of its length (unlike ordinary metal rods whose thermal resistance increases with length).  Heat pipes are commonly used to transport heat from one location to another.


Heat pipes work on the principle of evaporation and condensation.  A working fluid (frequently distilled water) evaporates inside one end of the heat pipe (the hot-end) absorbing heat in the process.  A partial vacuum inside the heat pipe allows the water to evaporate at a specific low temperature.  Once formed, the water vapor diffuses from an area of high vapor pressure (where it is being generated) to the other end of the tube where the vapor pressure is lower.


The vaporized fluid then condenses back to liquid (cold-end) and the heat is dissipated into the air from the metal cooling fins.  The working fluid returns to the hot end via capillary action thru an internal wicking structure (sintered metal coating, fine wire mesh, or grooves) so the heat pipe does not have to rely on gravity to recycle the working fluid.


The key to a heat pipe’s high efficiency is the latent heat of vaporization.  One gram of water absorbs 540 calories of heat when it changes state from a liquid to a gas (without any increase in temperature).  It then gives up this same amount of heat when it condenses back into a liquid.  By contrast, adding 540 calories of heat to 100 grams of copper (small heatsink) would raise its temperature 60ºC!

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