PCI Express* Add-in
Card Considerations
22 336521
Average Power Calculation
Interval Length in
microseconds(µs)
“T”
Ratio of Average Power1 in
Interval “T” Divided by
Maximum Sustain Power
Notes
≥ 1,000,000 µs (1 sec) 1 -
NOTES:
1. R =
average power during internal T
Max Sustained Power (ie.TDP)
.
2. This is also the max ratio of instantaneous power relative to maximum sustained
power.
3. ln() is the natural logarithm function.
4. Add-in Card must at all times and concurrently adhere to power excursion limits for
all time interval lengths as well as the limits defined for Power Supply Rail
Requirements in Table 3-5
.
5. Engineering Change Notice for up to 300 Watts (Work in Progress) will likely make
this table apply to all cards mounting the 12VHPWR connector.
Figure 3-1: PCI Express* CEM Add-in Card Power Excursion Limits Chart
3.1.1 PCIe* Add-in Card and PSU Power Budgets
Three dominant power demands dictate the total system power provisioning:
1. CPU power consumption
2. PCIe Add-in Card power level
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