Enhance cooling on COM Express Type 7 server-on-modules

October 13, 2016


Enhance cooling on COM Express Type 7 server-on-modules

The processing demands in carrier-grade telecommunication infrastructures, server farms, and distributed IoT edge and fog server applications are incr...

The processing demands in carrier-grade telecommunication infrastructures, server farms, and distributed IoT edge and fog server applications are increasing rapidly. The level of processing now needed is driving the development of a new generation of modular servers that are more powerful but smaller, and integrate more cores but consume less power per core.

Computer-on-modules that are designed in accordance to the brand new COM Express Type 7 specification are a perfect fit for such modular systems. For the first time, they feature multiple 10 Gbit Ethernet ports, more PCIe lanes supporting the latest solid state storage interfaces, and scalable server class performance with headless Intel Xeon processors that now offer up to 16 processing cores on a single die. But how do developers of high-density, server-like applications make full use of this power? When you are able to squeeze a sever module with a footprint of just 95 x 125 mm into a compact casing, or mount several modules in one high-density 19” 1U system, heat dissipation becomes critical.

This is especially relevant now that COM Express Type 7 server-on-modules use up to 65 W. If you want to harvest their full potential, you must have a very efficient cooling solution because these high-end embedded processors have been designed to automatically throttle back their core frequency – and thus, their computing power – to remain within their safe operating thermal envelope. By employing an efficient cooling solution, the CPU is able to operate at its maximum speed for more of the time, delivering consistently high computing performance the entire time the processor is cool enough. This makes an efficient cooling solution a decisive factor for application performance and reliability.

The COM Express specification defines a standard footprint for distributing the heat generated by the processing cores across a wider area, ensuring interchangeability is maintained between suppliers. Today, most standard cooling solutions for COM Express modules are limited to 35 W heat dissipation – primarily by the heat path from the processor to the heatspreader. But high performance server-on-module applications require more, as COM Express Type 7 cooling solutions must transfer up to 65 W. One solution would be to use physically larger cooling solutions, but for server modules, space is highly restricted. Thus, the cooling solution must be improved using more efficient solutions, such as the patented heat pipe technology developed by congatec. Unlike solid pipe designs, it harnesses the evaporation and condensation of a working fluid inside the pipes. The fluid circulates through capillary action, transferring heat as it does so. This has been shown to improve heat transport by up to 1,000 times over a heat pipe made from solid copper. The technology uses flattened pipes to transfer heat from the processor to the heatspreader plate while remaining within the specified mechanical dimensions. The design is appropriate even for fanless enclosures and flexible enough to meet customer-specific designs. By improving thermal efficiency, a COM Express Type 7 module can be deployed almost anywhere in a network, further driving innovation in the virtualized telecommunication and connected IoT industries.

Franz Fischer, congatec, Inc.