Buy the ARP T-Shirt! BIOS Optimization Guide Money Savers!
 
 13 July 2007
 N/A
  N/A
 Guides
 charge-n-go
 2.0
 Discuss here !
 280867
 
   
Mobile CPU Comparison Guide Rev. 11.4
There are so many CPU models that it has become quite impossible to keep up with the ... Read here
Western Digital My Passport Pro 2 TB Portable (Thunderbolt) Hard Disk Drive Review
Today, we are going to take a look at their latest portable hard disk drive for the M... Read here
   
Buy The BOG Book Subscribe To The BOG! Latest Money Savers!
PC Power Management Guide Rev. 2.0
Digg! Reddit!Add to Reddit | Bookmark this article:

Introduction

Computer performance have increased at an amazing rate in recent years, and unfortunately so does power consumption. An ultimate gaming system equipped with a quad-core processor, two NVIDIA GeForce 8800 Ultra, 4 sticks of DDR2 memory and a few hard drives can easily consume 200W without doing anything! To reduce power wastage, a few industry standards have been developed to make our computers work more efficiently.

In January 1992, Intel and Microsoft developed APM (Advanced Power Management) to manage power when a computer system is idling. Later in December 1996, the successor of APM – the Advanced Configuration and Power Interface (ACPI) specification was developed by Compaq, Microsoft, Intel, Phoenix and Toshiba as the industry open-standard power management interface. What's the difference? Let's take a look :

Advanced Power Management (APM)
Advanced Configuration and Power Interface (ACPI)

 • Cheap implementation, but not effective.
 • Application and driver send control to APM driver directly.
 • Device power is managed by its own driver.
 • Other hardware like CPU is managed by APM BIOS.
 • Power management state machine is done by APM BIOS since it is simple.

 • Implementation is more costly, but effective.
 • Application doesn't need to manage power.
 • Device driver uses ACPI to interface with hardware power management.
 • ACPI is abstract, thus OS and hardware can evolve separately.
 • Power management state machine is complex, hence handle by the operating system.

In this article, I will not go into APM as most PC use ACPI these days.

Sections

Topics

ACPI Power Management States

The Big Picture

Global System States (G-States)

G0 Working States
G1 Sleeping State
G2 Soft Off
G3 Mechanical Off
Summary

Sleeping States (S-States)

S1 State
S2 State
S3 State
S4 State
Summary

Device States (D-States)

D1 State
D2 State
D3 State
Summary

CPU Power States (C-States)

C0 State (Active)
C1 State (Halt)
C2 State (Stop Grant)
C3 State (Deep Sleep)
C4 State (Deeper Sleep)
C5 State
C6 State

C-States In Multi-Core Processors
Summary

CPU / Device Performance States (P-States)

Introduction
P-State Lookup Tables

C-States In Multi-Core Processors
Single Core
Dual Core
Quad Core (Intel)
Quad Core (AMD)

Other P-State Features
Super Low Frequency Mode
Combining CPU C-state & P-state
CPU Thermal Monitor

Conclusion

Conclusion



Next Page : ACPI Power Management States >>>

 

 
   
Western Digital WD TV HD Media Player Review
ASUS Launches Eee PC 1000HD, 1000H & 904HD!
The Reader's Guide To Using RSS
Jetart Xcool NP6900 Foldable Notebook Cooler Review Rev. 1.1
Virtual Memory Optimization Guide Rev. 4.1
Jetart Xpanel DT5000 Multi-Purpose Display Panel Review
512MB Mushkin PC4000 Dual Pack Review
Definitive Review of the Crucial PC2100 DDR-SDRAM

 


Copyright © Tech ARP.com. All rights reserved.