Thermal Considerations
VL-EPU-4460 Reference Manual
55
Table 18. Temperature Monitoring Programs
Operating System
Program Type
Description
Windows
Core Temperature
http://www.alcpu.com/CoreTemp/
Hardware Monitor
http://www.cpuid.com/softwares/hwmonitor.html
Open Hardware Monitor
http://openhardwaremonitor.org/
Linux
lm-sensors
http://en.wikipedia.org/wiki/Lm_sensors
Thermal Specifications, Restrictions, and Conditions
Graphical test data is in the section titled EPU-4460 Thermal Characterization, beginning on
page 56. Refer to that section for the details behind these specifications. These specifications are
the thermal limits for using the EPU-4460 with one of the defined thermal solutions.
Due to the unknown nature of the entire thermal system, or the performance requirement of the
application, VersaLogic cannot recommend a particular thermal solution. This information is
intended to provide guidance in the design of an overall thermal system solution.
Table 19. Absolute Minimum and Maximum Air Temperatures
Board
With Heat Plate
With Heat Sink
(HDW-416)
With Heat Sink + Fan
(HDW-416 + HDW-415)
VL-EPU-4460-EAP
-40 ° to +85 °C
-40 ° to +85 °C
-40 ° to +85 °C
VL-EPU-4460-EBP
-40 ° to +85 °C
-40 ° to +85 °C
-40 ° to +85 °C
VL-EPU-4460-ECP
-40 ° to +85 °C
-40 ° to +85 °C
-40 ° to +85 °C
Overall Restrictions and Conditions:
Ranges shown assume less than 90% CPU utilization.
Keep the maximum CPU core temperature below 100ºC.
The ambient air surrounding the EPU-4460 needs to be maintained at 85 ºC or below. This
includes the space between the two main boards as well as the space beneath an installed
Mini PCIe expansion board. A required overall airflow of 100 linear feet per minute (LFM) /
0.5 linear meters per second (LMS) addresses this requirement. If this air flow is not
provided, other means must be implemented to keep the adjacent air at 85 ºC or below.
Heat Plate Only Restrictions and Conditions:
The heat plate must be kept below 90 °C. This applies to a heat plate mounted directly to
another surface as well as when the HDW-408 heat pipe block is used.
Heat Sink Only Considerations:
At 85°C air temperature and 90% CPU utilization, there will be little if any thermal margin
to a CPU core temperature of 100 °C or the passive trip point (see test data). If this is the use
case, consider adding a fan or other additional airflow.
