White Paper - Power Management in Intel Architecture Servers

CPU %
P0
P3
P6
P8
X
Powers Watts
Power consumption with turbo mode enabled
135
130
125
120
115
110
105
100
20 30 40 50 60 70 80
X
X
X
X
Figure 9. Power variation with P-state change and CPU utilization, with turbo mode�
Several conclusions can be drawn:
•Thehighestperformancestateofaturbomode-enabledsystem
consumes less power overall (an average of 110 watts versus 120
watts without turbo mode enabled).
•TorunCPUloadshigherthan50percent,aperformancestateofP6
can achieve the same power consumption in a turbo-mode enabled
server, as a lower performance state of P4 in a server with turbo
disabled.
•Turbomodedisabledresultsinlesspowerconsumptionwithlighter
CPU loads—P4 in Figure 8. Also, a server consumes more power with
turbo mode enabled—P0 in Figure 9.
To summarize, at high server workloads, the Intel® Xeon® processor
5500 series server should have turbo mode enabled to extract
higher performance and lower power consumption from the Intel® Xeon®
processor 5500 series. At lower workloads, turbo mode should be disabled
to save a server’s power consumption.
At the data center level, it has been shown [4] that rack densities
can be increased by 20 to 40 percent as long as all the servers are
not running at their fully rated power capacity. This allows over-
provisioning of compute capacity in a rack, while staying within the
rack’s power envelope. An obvious benefit is to assign priority to
different workloads on different servers at different times of the
day. This is akin to a mobile phone operator designing the network
capacity to be below the theoretical peak needed because subscribers
do not make calls simultaneously. Substantial savings can result for
data center operators using Intel’s NM technology, while still being
able to meet their different customers’ peak loads occurring at
different times.
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White Paper: Power Management in Intel® Architecture Servers