Hardware Secrets
Home | Camera | Case | CE | Cooling | CPU | Input | Memory | Mobile | Motherboard | Networking | Power | Storage | Video | Other
Content
Articles
First Look
Gabriel's Blog
News
Reviews
Tutorials
Main Menu
About Us
Awarded Products
Compare Prices
Datasheets
Dictionary
Download
Drivers
Forums
Links
Manufacturer Finder
Newsletter
On The Web
RSS Feed
Test Your Skills
Twitter
Newsletter
Subscribe today!
Search




Recommended
The Winn L. Rosch Hardware Bible, 6th Edition (2 Vol. Set)
The Winn L. Rosch Hardware Bible, 6th Edition (2 Vol. Set), by Winn L Rosch (Que), starting at $2.31
Home » CPU
Inside Intel Nehalem Microarchitecture
Author: Gabriel Torres
Type: Tutorials Last Updated: August 26, 2008
Page: 5 of 7
$ Check REAL-TIME pricing for AMD Black Edition Phenom II X4 955 / 3.2 GHz processor HDZ955FBGIBOX $.
Tech Depot: $23.40

Power Management Enhancements

Transistors inside the CPU work as a switch, with two possible states: conductive (a.k.a. “saturation mode”), working as a closed switch, and non-conductive (a.k.a. “cut-off” mode), working as an open switch. The problem is when they are on their non-conductive state in theory they shouldn’t allow any current to flow, but a small amount of current still flows. This current is called leakage and if you add up all leakage currents you have a significant amount of current (and thus power) being wasted and unnecessary heat being generated. One of the challenges in designing CPUs in recent years has been trying to eliminate leakage current.

Nehalem brings a power control unit inside the CPU in order to better manage power (see Figure 8). This unit reduces leakage current and also allows the new “Turbo Mode”, which we will discuss on next page. Basically, the CPU can now have different voltages and frequencies for each core, for the units outside the cores, for the memory controller, for the cache and for the I/O units. On previous CPUs, all cores had to run at the same clock rate but on Nehalem-based CPUs each core can be programmed to run at different clock rates to save power.

Nehalem Core i7
click to enlarge
Figure 8: Power control unit.

The embedded power control unit can now switch off any of the CPU cores, feature not available on mobile Core 2 CPUs. In fact now the CPU can put any core into the C6 (“deep power down”) power state independently of the state under the remaining cores are running. This allows energy savings when you are running your PC normally but one or more cores are idle and thus can be shut down.

Pages (7): « 1 2 3 4 [5] 6 7 »
Print Version | Send to Friend | | Bookmark Article | Comments (2)

Related Content
  • Details on Intel’s Forthcoming 45 nm Manufacturing Technology
  • Core 2 Duo E6750 Review
  • Core 2 Duo E7200 CPU Review
  • Core 2 Duo, Core 2 Quad, Phenom X3 and Phenom X4: Which One is the Best USD 200 CPU?
  • Everything You Need to Know About The QuickPath Interconnect (QPI)

  • Recommended Deal.
    Power Supply VX450W 450W ATXCorsair CMPSU-450VX VX450W ATX12V & EPS12V Power Supply 450w VX Series 12v ATX 80 Plus Certified C3PLRL


    Buy.com: $74.42 Wal-Mart: $89.98
    Newegg: $64.99 TigerDirect: $79.99

    RSSLatest News
    IN WIN LAN Party in Southern California
    November 20, 2009 - 12:37 PM PST
    Patriot Announces PS-100 SSD Series
    November 19, 2009 - 7:30 AM PST
    Antec Launches TPQ-1200 PSU
    November 18, 2009 - 11:30 AM PST
    AMD/ATI Launches Radeon HD 5970
    November 18, 2009 - 10:18 AM PST
    OCZ Launches Colossus SSD Series
    November 17, 2009 - 1:39 PM PST
    NZXT Unleashes Tempest EVO Mid-Tower Case
    November 17, 2009 - 1:06 PM PST
    nVidia Launches GeForce GT 240
    November 17, 2009 - 10:18 AM PST
    Arctic Cooling Announces Accelero TWIN TURBO PRO VGA Cooler
    November 16, 2009 - 11:46 AM PST
    PowerColor Announces PLAY! HD5770 Video Card
    November 13, 2009 - 12:51 PM PST
    G.Skill Announces Falcon II SSD Series
    November 11, 2009 - 3:31 PM PST
    .:: More News ::.

    RSSLatest Content
    Ultra X4 500 W Power Supply Review
    Seagate Barracuda XT 2 TB Hard Disk Drive Review
    Nintendo Wii Fit Plus Review
    AMD ATI Chips Comparison Table
    nVidia Chips Comparison Table
    Gigabyte G41M-ES2L Motherboard
    Netflix on Playstation 3 Review
    CM Storm Sentinel Advance Mouse Review
    Titan Skalli CPU Cooler Review
    Nexus RX-6300 630 W Power Supply Review
    Gigabyte P55-UD6 Motherboard
    Nintendo Wii Review
    SilverStone Grandia GD04 Case Review
    Can We Trust the 80 Plus Certification?
    NZXT Gamma Case Review

    Our Most Popular Articles
    Maximum CPU Temperature
    1,078,673 views
    How to Find Out Your Motherboard Manufacturer and Model
    706,700 views
    nVidia Chips Comparison Table
    679,463 views
    Connecting Two PCs Using a USB-USB Cable
    593,773 views
    How To Correctly Apply Thermal Grease
    562,772 views
    AMD ATI Chips Comparison Table
    560,373 views
    ATI Radeon X1300 Pro Review
    488,023 views
    ATI Radeon X1600 XT Review
    477,180 views
    How To Perform a BIOS Upgrade
    394,737 views
    Sempron vs. Athlon XP
    338,601 views

    Latest Threads in Our Forums
    Dell Inspiron 6000 Powers but will not boot...
    by Merman
    Ultra X4 500 W Power Supply Review
    by Merman
    IN WIN LAN Party in Southern California
    by Hardware Secrets Team
    Getting A Hard Copy
    by Trevorrross
    Am I Making The Right Choice?
    by need2know
    Is it available to mount the Zalman cooler?
    by Olle P
    dsl modem prob
    by Sherry
    Seagate Barracuda XT 2 TB Hard Disk Drive Review
    by Hardware Secrets Team
    Overclocking a dell xps 410
    by 6dracing
    How to recover mp3's, pdf & chm files, applications from formated harddrive partition
    by tomahawk 1705
    .:: Visit Our Forums ::.


    © 2004-9, Hardware Secrets, LLC. All rights reserved.
    Advertising | Legal Information | Privacy Policy
    All times are Pacific Standard Time (PST, GMT -08:00)