Copyright by William Lloyd Bircher 2010 - The Laboratory for ...

efficiency rather than performance. This leads to greater variation in power consumption
compared to a server since power management features reduce power greatly during low
utilization. Server systems tend to employ less aggressive power savings. Therefore,
power at low utilization is greater and overall variation is lesser. This difference is
evident in the analysis of average subsystem-level power in Tables 5.1 - 5.2 and 5.6. The
power management implementation in the desktop system also requires the use of more
extensive power models. Rather than only needing to consider CPU clock gating and
DRAM power down modes, the desktop system model must consider DVFS, chipset link
power management, disk and GPU power management. The wider range of power
consumption also leads to greater temperature sensitivity.
Table 5.3 System Comparison
Platform
Segment
Server Desktop
Manufacturer Intel AMD
Processor(s) Quad-socket 130nM
2.8GHz
Dual-core 45nM 2.0GHz
Memory 8GB DDR-200 4GB DDR3-1066
Power CPU Clock Gating CPU Clock Gating and DVFS
Management DRAM Power Down DRAM Power Down and Self
Refresh
Chipset Link Disconnect
Harddrive Spin Down and
ATA modes
GPU Clock Gating
Graphics Rage ProXL RS780
Observable
CPU
CPU
Subsystems
Chipset
Chipset
Memory
Memory
I/O
Memory Controller
Disk
85
GPU
Disk