Generic Thermal Solution
R
20
Intel
®
845GE / 845PE Chipset (G)MCH Thermal Design Guide
3.3
Generic Thermal Solution Thermal Operating Point
The Thermal Operating Point (TOP) is defined as the thermal resistance of the TIM at the
design force of the clip and retention mechanism plus the thermal resistance of the heatsink at
the specified airflow speed. The thermal resistance of the heatsink (TRHS) is given by the
following equation:
TRHS = (T
case
– T
local_ambient
) / (% TDP dissipated via heatsink)
Thermal simulation results show that as airflow increases upstream of the 845GE/845PE chipset
generic thermal solution, the percentage of TDP that leaves via the top of the package increases
(see Table 8).
Table 8. TDP Dissipation for Various Airflow Speeds
Upstream Airflow Speed
(
lfm
)
% of TDP Dissipated via
Intel Thermal Solution
% of TDP Dissipated via the
4-Layer JEDEC Board
50 70%
30%
100 75%
25%
150 77%
23%
3.4
Generic Thermal Solution Simulation
A Computational Fluid Dynamics (CFD) model of the (G)MCH has been developed for use with
the commercially available thermal analysis tool “Flotherm” (version 2.1 or later). This model
can be used to evaluate package thermal limits and cooling methods. Modeled (G)MCH
components are shown in Figure 8.
Figure 8. Intel
®
(G)MCH Components Modeled
package_overview
Die
C4 Bumps
Substrate
Underfill
Contact your Intel Field Sales representative to order the thermal models and user’s guides.
