Intel X3350 Design Guide - Page 63

Thermal Solutions 7.6.4 7.6.5 Increased IMON accuracy may provide more Intel® TBT benefit on TDP limited applications, as compared to lower ΨCA, 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 compared to when Intel® TBT is be more likely disabled. This to operate may result above TCONTROL, as in higher acoustics. 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 Section 6.2.1 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. 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. Figure 7-7 is a 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 Ψca would be 0.50ºC/W at 55ºC ambient which falls below the thermal profile for the 60W processor. Intel® Xeon® Processor C5500/C3500 Series and LGA1366 Socket Thermal/Mechanical Design Guide 63 August 2010 Order Number: 323107-002US