Table of Contents
Advertisement
Product Specifications
2.4
Thermal Specifications
2.4.1
External Ambient Conditions
To ensure proper operation and reliability of the (G)MCH, a minimum airflow speed of 50 lfm
(linear feet per minute) must be present as measured 1 inch in front of the air inlet side of the
845GE/845PE chipset generic thermal solution. The thermal designer must carefully select the
location to measure airflow to get a representative sampling. (Note, These environmental
specifications are based on a 35 °C system external temperature measured at 5000'). The
maximum recommended local ambient air temperature (T
chassis and system design. The assumptions for local ambient temperature are shown in Table 3
below and are based on an 8° temperature rise from the processor local ambient temperature.
Table 3. Maximum (G)MCH Local Ambient (T
®
Pentium
Mother Board (FMB) Targets
NOTE: The values for processor local ambient temperature are provided for reference only; In case of
discrepancies, the values in the respective processor datasheet supersede the values listed above.
The amount of airflow also directly impacts the BIOS settings required for the memory thermal
management, which is controlled by the chipset. Memory thermal management needs to be set in
the BIOS for systems with under 100-lfm airflow to the (G)MCH and under 100-lfm airflow to
the memory. To determine the memory airflow, Figure 3 shows the correct location for air speed
probes in relation to the DIMM. The location of the probes (U1 and U2) should be elevated to the
center of the DIMM, and 0.25" from the edges as shown. The average should be taken from the
measurements at locations u1 and u2 shown below for determining the airspeed setting.
Figure 3. DIMM Airflow Measurement Location
0.25 in
U1
14
4 Processor Flexible
Pentium
Ambient (T
FMB1
FMB2
®
Intel
845GE / 845PE Chipset (G)MCH Thermal Design Guide
) for the (G)MCH is influenced by
A
) Recommendations
A
®
4 Processor Local
) Assumptions
A
45 °C
42 °C
(G)MCH Local Ambient (T
)
A
Assumptions
53 °C
50 °C
0.25 in
U 2
R
Advertisement
Table of Contents
