Thermal Solutions
Intel
®
Xeon
®
Processor C5500/C3500 Series and LGA1366 Socket
Thermal/Mechanical Design Guide
August 2010
63
Order Number: 323107-002US
Increased IMON accuracy may provide more Intel
®
TBT benefit on TDP limited
applications, as compared to lower
Ψ
CA
, as temperature is not typically the limiter for
these workloads. See Voltage Regulator Module (VRM) and Enterprise Voltage
Regulator-Down (EVRD) 11.1 Design Guidelines for more information regarding IMON
accuracy.
With Intel
®
TBT enabled, the processor may run more consistently at higher power
levels (but still within TDP), and be more likely to operate above T
CONTROL
, as
compared to when Intel
®
TBT is disabled. This may result in higher acoustics.
7.6.4
Absolute Processor Temperature
Intel does not test any third-party software that reports absolute processor
temperature. As such, Intel cannot recommend the use of software that claims this
capability. Since there is part-to-part variation in the TCC (thermal control circuit)
activation temperature, use of software that reports absolute temperature can be
misleading.
See
for details regarding use of IA32_TEMPERATURE_TARGET register to
determine the minimum absolute temperature at which the TCC will be activated and
PROCHOT# will be asserted.
7.6.5
Custom Heat Sinks For UP ATCA
The embedded-specific 60W SKU was targeted for NEBS compliant 1U+ systems and
UP ATCA configurations with custom thermal solutions. In order to cool this part in a
single wide ATCA slot, a custom thermal solution will be required. Unique solutions like
the UP ATCA processor will be very configuration specific so, the thermal solution for UP
ATCA was not fully designed with retention and keep-out definitions.
good example of a custom thermal solution for the UP ATCA processor.
To cool the additional power of a 60 W processor in ATCA, the heatsink volume had to
grow. The assumption was that the heat sink could not grow wider because of VR and
Memory placement so a Remote Heat Exchanger (RHE) was used. The RHE is attached
to the main heat sink with a heat pipe. The RHE gives additional convective surface
area and gives the thermal solution access to more air. Samples of the following design
were ordered and tested for thermal performance only.
Flotherm analysis shows that the following design can cool an LGA1366 TTV in an ATCA
blade at 30 CFM. The heat sink
Ψ
ca would be 0.50ºC/W at 55ºC ambient which falls
below the thermal profile for the 60W processor.