PC Power Management Guide

Discussion in 'Reviews & Articles' started by Dashken, Jul 8, 2007.

  1. charge-n-go

    charge-n-go Newbie

    That is the sole purpose of P-state (Performance State). It manages the processor to give the best performance per watt. A simple question for you: do you want to use Microsoft Word at 65W or 25W if the performance difference is negligible? This is how P-state manage the power according to the CPU load. However, since the transition from one P-state to another is within nano seconds, and the fastest detection tools we have can only report at probably 250 micro second range. So you won't see the changes until it is stabilized at the lowest / highest CPU clock speed for some time.

    And yes, i am very sure EIST = P-state power management. It is called Geyserville technology in Intel.

    In C1, the processor executes nothing. The execution unit is completed stalled as mentioned in guide. So there is no point to through every level of P-state. It will go straight into the lowest P-state which gives u 6x ratio. The purpose of using lowest P-state in C1, C2 and etc. was already mentioned in the guide too.

    If you have any doubts. please read the ACPI specification. It mentioned clearly that P-state power management resides in C0 state.
    Last edited: Aug 2, 2007
  2. Chai

    Chai Administrator Staff Member

    I also noticed a significant power usage drop at idle compare to EIST disabled.

    I guess I can forget what ever I'm going to do now. Haha. Thanks for your info.
  3. charge-n-go

    charge-n-go Newbie

    Welcome dude :)

    Yea, because C1 is sleep state, the whole core is put down into HALT mode. C0 is active, so even the processor runs at lowest clock speed, there are still millions of transistor working. C1 actually runs at highest clock speed, but C1E brings it down to lowest clock speed. This is more logical lo.

    anyway, if u still have doubts, can post here or IM me directly @ YM ! cyeeyong
  4. Chai

    Chai Administrator Staff Member

    But the thing is C1E wasn't enabled. And when it's enabled, the voltage dropped to 1.1V. I'm sure without EIST, the C1 state will always be active.
  5. charge-n-go

    charge-n-go Newbie

    Yes you are right. C1 is an automated mechanism. The 'E' behind is just a new feature to enable the clock and voltage throttling before C1 kicks in.
  6. graysky

    graysky ARP Reviewer

    Is there an application that can display the current C or P state of the chip? I have noticed that coretemp ALWAYS show C0 state for my chip even when speedstep kicks in...
  7. firefly

    firefly Newbie

    Request for advice ... :p

    Hi YongGrand and charge-and-go,

    Been reading this forum and the 2 of you really sounded like a "sifu" to me, so .. was wondering .. whether I can get some advice from you guys ... ;)

    Was thinking to get a Celeron 420 too .. coz am going to put it in my room and was thinking of on it 24x7 .. for BT downloading ... :D

    So, I was wondering .. will I get any problem if I were to on the PC 24x7? Will it ever get over-heated? Do I need to get any lightning arrester to protect my PC and modem? If so, can recommend any good one? :)

    Also, I wish to run Vista Home Premium. Is there any additional hardware requirement to run Windows Aero?

    Lastly, is this Celeron 420 fast enough for day to day use? What would be the ideal RAM for it? Care to advise?

    Thanking you guys in advance ... and keep up the good work by sharing more knowledge and information ... :clap:
  8. The_YongGrand

    The_YongGrand Just Started

    Hello and welcome! :wave:

    Well the Celeron 420 (note the absence of D - it's for the older Cedar Mill and Prescott cores only) is quite a good buy if it's much cheaper! Yes the Celeron 420 is a very ideal one for HTPC and BT rig since it involves only a mere 35Ws. If you don't believe it - the heatsink of Celeron 4xx series are 1/2 of the size of the original stock 775 heatsink. But the thing is, the price of AMD X2 3600+ (not sure whether it is still sold!) looks tempting enough for you to buy that one instead of the Celeron 420. And the Athlons are also equipped with Cool and Quiet, so the throttling of speed will be even less than 35W for the Athlons. The Single-core Athlons are equipped with the same feature too, and it'll not be a worry for you since the performance of both 1-core Athlons64 and Celeron 4xx are almost the same.

    The performance of Celeron 420 is comparable to Pentium 4 531 - I tested it. So it'll be a small outline of which one should it be belong to. Too bad it doesn't have a Speedstep, only C1E is supported. If speedstep is available, the Celeron 420 could have reach even lower wattages! Maybe it'll fall a little bit behind in terms of multitasks because the absence of HT.

    For the Aero interface, a newer Intel GMA should work (I think it's the 9000 series!) or any cards equivalent or better than Geforce FX5200, which is the minimum one.

    Hope that helps! :)

    For the lightning arrestor - try the Cal-Lab. For the PC - you might need a UPS or a AVR. :)
  9. firefly

    firefly Newbie

    YongGrand .. you rock!!!

    Hi YongGrand,

    Thank you so much for such a prompt reply and those useful info. Truly appreciate your input ... :D

    Actually, there is this promo between Citibank, HP and TMnet .. and HP is giving this Compaq Presario SR5122CF CTO Desktop PC for the RM99 per month package.

    Below is the full spec of this PC.

    Model Number SR5120CF
    Product Number GN672AA
    Sku Status
    Microprocessor Intel® Celeron® processor 420
    1.6GHz, 512KB L2 Cache, EM64T, Execute Disable Bit, 800Mhz FSB
    Processor Bus Speed 800MHz
    Cache 512KB Advanced Transfer Cache
    Chipset Intel® 945GC Express Chipset
    Memory 512MB DDR2
    Expandability expandable up to 2.0 GB with discard
    Memory Speed PC2-4200 / 533MHz
    Total Memory Slots 2 DIMM
    Available Memory Slots 1 DIMM
    Audio Integrated Intel High Definition Audio, 5.1 Surround Sound Ready
    Hard Drive 80.0 GB * Serial ATA hard drive at 7200RPM *Gigabyte(GB) is defined as 1 billion bytes
    Optical Drive 1 CD-RW/DVD Combo Drive (48x32x48x16x)
    CD: 48x write; 32x-rewrite; 48x read max speed
    DVD: 16x read max speed
    Optical Drive 2 None
    Video Graphics Intel® GMA 950 Graphics
    Video Memory Up to 64MB shared memory
    Communication None
    Wireless LAN None
    Tv Tuner None
    Remote Control Module None
    Networking Integrated 10/100 BaseT network interface (Broadband Ready)
    Digital Media Reader None
    Front Access None
    Rear Access 2 USB 2.0, 2 PS/2, Line-in, Line-out, Mic-in, LAN
    Keyboard Compaq Multimedia Easy Access Internet Keyboard
    Mouse Compaq Optical, 2-button PS2 scroller mouse
    Total Expansion Slots 1 PCI Express (x16), 1 PCI Express (x1), 2 PCI
    Available Slots 1 PCI Express (x16), 1 PCI Express (x1), 2 PCI
    Total Drive Bays External (2) 5.25", (2) 3.5"; Internal (2) 3.5"
    Available Bays External (1) 5.25", (2) 3.5";
    Service And Support 1 year (onsite) limited warranty with up-and-running phone support for first 30 days
    Vista Logo Free DOS Operating System
    Platform brand (Intel Viiv or AMD Live) None
    OS & SOFTWARE None
    Operating System None
    Productivity & Finance None
    Encyclopedia None
    Home Entertainment None
    Entertainment None
    Games None
    Media Burning & Video Editing Software None
    Digital Photography None
    Video Editing Software None
    Video Editing Software None
    Internet & online None
    Anti-Virus Software None
    PC Help & Recovery PC Doctor
    PC Help & Recovery None
    PC Help & Recovery None
    PC Help & Recovery None
    PC Help & Recovery None

    Umm .. what do you think about this spec? Any good? ;)

    Honestly, I am OK with it .. except the casing doesn't come with a front panel, i.e. I won't have any USB ports in front of the PC. Gosh .. this will be so inconvenient for me .. coz my room is small .. and the CPU is planned to be hidden underneth my table. Imagine I will need to take the CPU out each time I need to use the USB port at the back. Oh boy .. it's not going to be pleasant!!! :evil:

    Don't know why HP is so cheapskate to remove the front panel. My friend got his HP PC through the TMnet promo in June .. and his model comes with a front panel ... :wall:

    So, I was wondering .. is there a way to add the front panel later .. through DIY? I understand the front panel comes with the casing .. hmm .. do they sell separately on this? Is it difficult to install? Care to advise? :)

    Also, was thinking to install Windows Vista Home Premium on this PC. Do you think this will be a wise move? Or, I shall stick with Windows XP Pro SP2. Hmm .. but kinda bored with XP and wish to experience the new Vista. But .. heard a lot of bad things about it wor ... ummm ...
  10. Chai

    Chai Administrator Staff Member

    Maybe you should create a new thread. This is about PC Power Management. :)
  11. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Yeah, you should create a new thread for this. :mrgreen:

    Chai, maybe help him split out his posts? :think:
  12. firefly

    firefly Newbie

    Ooops ... :oops:

    Hi Chai,

    I am truly sorry about this. But .. I have no clue how to split or to create a new thread. Could you help me out .. please? Thank you so much!! :)

    By the way, will YongGrand able to see my post after it is moved elsewhere? Care to advise?

    Kind regards.
  13. Chai

    Chai Administrator Staff Member

  14. firefly

    firefly Newbie

    Thank you! :)

    Hi Chai,

    Thank you so much for your help!! And the very prompt reply too. Gosh .. you are super efficient ... hehehe ... :clap:

    Anyway, I hope YongGrand can see the post and reply me there ... :)

    Of course, I will appreciate any input from others too .. coz I know there are so many technical savvy "guru" and "sifu" over here who are truly nice .. kind and helpful .... ;)

    Thank you so much guys!! cya at my thread ... :wave:

Share This Page