Intel
®
945G Express Chipset GMCH Thermal Design Guide
Product Specifications
is a requirement for a sustained power level equal to TDP, and that the case temperature must be
maintained at temperatures less than T
C-MAX
when operating at power levels less than TDP. This
temperature compliance is to ensure chipset reliability over its useful life. The TDP value can be
used for thermal design if the chipset thermal protection mechanisms are enabled. Intel chipsets
incorporate a hardware-based fail-safe mechanism to keep the product temperature in spec in the
event of unusually strenuous usage above the TDP power.
2.5.1 Methodology
2.5.1.1 Pre-Silicon
In order to determine TDP for pre-silicon products in development, it is necessary to make
estimates based on analytical models. These models rely on extensive knowledge of the past
chipset power dissipation behavior along with knowledge of planned architectural and process
changes that may affect TDP. Knowledge of applications available today and their ability to stress
various components of the chipset is also included in the model. Since the number of applications
available today is beyond what Intel can test, only real world high-power applications are tested to
predict TDP. The values determined are used to set specific data transfer rates. The projection for
TDP assumes GMCH operation at T
C-MAX
. The TDP estimate also includes a margin to account
for process variation.
2.5.1.2 Post-Silicon
Once the product silicon is available, post-silicon validation is performed to assess the validity of
pre-silicon projections. Testing is performed on both commercially available and synthetic high
power applications and power data is compared to pre-silicon estimates. Post-silicon validation
may result in a small adjustment to pre-silicon TDP estimates.
2.5.2 Application
Power
Designing to the TDP can ensure a particular thermal solution can meet the cooling needs of
future applications. Testing with currently available commercial applications has shown they may
dissipate power levels below the published TDP specification in Section 2.5.3. Intel strongly
recommends that thermal engineers design to the published TDP specification to develop a robust
thermal solution that will meet the needs of current and future applications.
2.5.3 Specifications
The GMCH is estimated to dissipate the Thermal Design Power values provided in Table 3 when
using two (2) DIMMs of 667 MHz dual channel DDR2 with a 1066 MHz processor system bus
speed. The graphics core is assumed to run at 400 MHz. Without thermal solutions, FCBGA
packages have poor heat transfer capability into the board and have minimal thermal capability.
Intel requires that system designers plan for an attached heat sink when using the GMCH.
Table 3 GMCH Thermal Design Power Specifications
Component
System Bus Speed
Memory Frequency
TDP Value
Intel
®
82945G Express Chipset GMCH
1066 MHz
667 MHz
22.2 W
10
Order #308643
