Over the years as computer processors increased in speed, the resulting heat generated by the processors continued to climb. At first this could be solved by adding a passive heatsink to the top of the processor, but as the heat kept growing it was necessary to add fans to move air over the heatsinks to increasing the cooling ability. Heatinks then began to grow in size dwarfing the smaller processors beneath them. The problem has become so pronounced that enthusiasts and even some companies now including water cooling radiators to cool down the processors.
Water and electronics don't mix well and it requires a lot more diligence to ensure a system is properly cooled. As a result, engineers have come up with a number of new air cooling solutions to try and move heat away from the processor and outside of the computer. This article takes a look at the rise of the horizontal CPU cooler.
Heat Pipes
Before horizontal coolers entered the market, another key cooling technology had to be developed. The heat pipe is a method of moving heat from one point to another through evaporation and condensation. Essentially, a small hollow pipe of aluminum or copper is filled with a small amount of liquid and sealed. At the bottom of the pipe, the heat causes the liquid to evaporate and then travel to the cooler end of the pipe. When it reaches this point it then condenses, releases the heat to the material at that end and then is brought back to the hot end through small channels in the pipe walls.
This is an important development as it allowed the transfer of heat from very hot to cooler portions on the heatsink with greater efficiency than the standard radiation method. These heat pipes began to show up on traditional CPU coolers as a means to allow the heat from the portion directly attached to the heatsink to spread out over the larger area of the heatsink. This allowed for larger heatsinks but the motherboard still restricts the physical size due to capacitors and connectors that surround the CPU socket.
Air Flow The flow of air over the heatsink is crucial in moving the heat out of the cooler and into the external environment. Traditional CPU cooler designs place a fan on the top of the heatsink and blowing down onto the cooler and CPU. While this was an effective method, as the amounts of heat generated by the CPU increased, the turbulence of the air circulating around the board and case can't move the hot air out of the case as effectively. This is where the horizontal heatsink designs come in.
Rather than the heatsink being designed with the fins pointing down at the CPU, the material is designed so that air flows over the CPU through the heatsink. This allows for smaller volumes of air to be moved as it generally flows from the front of the case to the back rather that circulating around the interior of the case. If the case has proper venting at the front and rear of the case near the CPU, this can be so effective at removing heat that no fan is needed on the heatink to move air over it. This is one of the key design elements of the BTX case design.
Surface Area
In addition to the air flow, horizontal heatsinks also generally provide better heat dissipation from the traditional design thanks to increased surface area. Due to the motherboard CPU socket area limitations, traditional heatsinks have little room to fit into the design. Many third party performance heatsinks have compatibility charts to let you know if it will work with your motherboard layout. Horizontal heatsinks get around this problem by increasing the vertical size of the heatsink rather than spreading out around the board.
This increase height allows a larger number of plates to be stacked around the heatpipes to capture the radiant heat. With the plates stacked vertically, it also increases the amount of surface area for the plates to have air move over them and pull heat away. The drawback to this is that the increased height can be problematic with many desktop cases. If the case doesn't have enough room for the vertical size of the heatsink, then a traditional cooler would need to be used.
Should You Use One?
Horizontal heatsinks are best used for those looking to build a low noise system. With the improved cooling performance, the ability to use a horizontal heatsink as a passive cooler or with a larger low speed fan can greatly reduce the amount of noise generated by the heatsink. The improved performance can be beneficial to those looking to overclocking their processor, but liquid cooling is generally the better choice for these individuals as performance generally is more important than noise.
Then again, there are space constraints within the computer case that will determine if it really can support the use of the horizontal cooler. Be sure to check and make sure that your computer motherboard is compatible and the computer case has sufficient room to allow for it.
