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capability compared to traditional modular chassis architectures. Additionally, the independent airflow zones allow for

more granular fan control algorithms which increase fan speeds only when and where it is needed to further increase

efficiency.

COMPUTE & STORAGE SLED COOLING

Compared with previous modular chassis from Dell and competitors, the MX7000 chassis contains no vertical

midplane that would restrict the airflow through the chassis. Instead, sleds within the chassis mate directly with rear

IOMs in A1/A2/B1/B2 slots through direct orthogonal interconnects. In the space between the A1/A2 and B1/B2 IOMs,

the MX7000 80mm fan modules are directly ducted to the sleds to pull air through compute and/or storage sleds in

Zone 1. Multiple chassis seals ensure that the low pressure generated by the rear 80mm fans stays within Zone 1.

Containing the low pressure is critical in enabling the increased sled storage density with support for up to six 2.5”

HDDs in the front end of the Dell EMC PowerEdge MX740c.

Figure 2 below provides a cross-sectional view of the chassis to highlight the Zone 1 airflow path thru a compute sled.

Cool air enters thru the hard disk drive (HDD) bay of the sled before cooling the CPUs, memory, and peripheral

components. The 80mm fan modules at the rear of the chassis pull air through the sleds and exhaust hot air out of the

system. Fans are positioned in line with the critical heat loads, the CPUs, to avoid complex ducting and provide

efficient cooling. Since there are no downstream components in this flow path, a large temperature difference is

allowed across CPUs to maximize processor TDP support with headroom to scale with future generations.

Figure 2: Cross-sectional view of airflow through Zone 1 of the MX7000 chassis, showing cooling of Compute

sleds. Air enters at front of chassis (on left) and exhausts thru rear of chassis (on right). Other airflow zones

have been greyed out in this graphic.

NETWORKING AND I/O

Due to their internal layout, modular infrastructures have traditionally been forced to cool networking fabrics with

preheated air from upstream components or through tortuous pathways that limit the amount of cooling airflow

available. With limited airflow capability, the ability to support future networking and I/O technologies becomes more

difficult as these technologies continue to advance at a rapid pace. In contrast, the MX7000 chassis has been

designed for fresh inlet air delivery to all rear IOMs and Chassis Management Modules (CMMs) via four dedicated fan

modules in the front of the chassis. The direct airflow path is shown in the cross-sectional graphic in Figure 3 (at the

top of Page 3), which highlights airflow Zone 2. The four 60mm fan modules arranged vertically share a large plenum

down the center of the chassis. An air ducts splits the airflow into an upper path which cools IOMs A1/A2 and a lower

path to cool IOMs B1/B2/C1/C2 and CMMs. The fresh air entering these modules ensures the MX7000 chassis can

run fans at lower speeds and operate over a wider range of environmental conditions as well as providing sufficient

airflow capability for future networking technologies.