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Internal Use - Confidential
Dell PowerEdge Servers: New PSU Layout Delivers
Improved Airflow and PCIe Feature Set
Split Power Supplies
The layout of previous generations of Dell PowerEdge rack servers
utilized two power supplies grouped on one side of the chassis. Dell’s
next generation of PowerEdge servers improves the mechanical design
with the two power supplies split – one on each side of the chassis. This
new system and power supply layout offers several tangible benefits
over the older system design.
Balanced Airflow
In prior generations, the location of the inner power supply was near the
CPU exhaust airflow. Due to the proximity to the CPU, the PSU was
continually exposed to air that is heated to high temperatures from
moving through the CPU heatsink. With each new CPU refresh, power
continues to increase and PSU cooling becomes exponentially more
challenging. Additionally, the PSU location compounded the thermal
challenges because it was also an obstruction to airflow moving freely
through the CPU heatsink.
The split power supply placement in the next generation of PowerEdge
servers allows for both low temperature airflow for PSU cooling and less
obstruction for cooling high power CPUs. The result is that system
airflow is balanced across the width of the system providing more
uniform airflow for CPU, Memory, and PCIe cards in the rear of the
chassis.
Support for Gen4 PCIe
One of the goals of the new architectures in the next generation of
PowerEdge servers is to support faster I/O speeds, such as PCIe Gen 4,
and beyond. PCIe Gen 4 doubles the lane speed to 16GT/s from the
previous generation. A key element in PCIe performance is the length of
PCIe traces. With the new system layout, a main goal was to shorten
the overall PCIe trace lengths in the topology, including traces in the
motherboard. By positioning PSU’s at both edges, the I/O traces to
connectors can be shortened for both processors. This is the optimal
physical layout for PCIe Gen 4 and will enable even faster speeds for
future platforms. The shorter PCIe traces translate into better system
costs and improved Signal Integrity for more reliable performance across
a broad variety of customer applications.
Tech Note by
Robert Curtis
Corey Hartman
Kim Kinahan
Summary
The next generation of
PowerEdge servers brings
a new Power Supply layout
that allows for improved
system cooling and helps
enable support for Gen4
PCIe cards.
Purchase with confidence,
knowing that these system
improvements help ensure
that the next generation
PowerEdge server
continues to deliver best-in-
class features.