Reducing The Power Consumption Of Overclocked PCs

Discussion in 'Reviews & Articles' started by Dashken, May 4, 2008.

  1. Dashken

    Dashken Administrator!

    Now, that must sound pretty inane. After all, overclockers employ all kinds of power-guzzling methods to improve their CPU's overclockability. However, there are many good reasons to do so.

    In this guide, we will not just look at theoretical tips on reducing power consumption in overclocked PCs, we will also show you how well they work in real-life situations. Best of all, we will show you why they will improve your PC’s power efficiency without any real loss in performance.

    Here's a quote from the article :-

    Link : Reducing The Power Consumption Of Overclocked PCs
  2. Mac Daddy

    Mac Daddy Pickin' Da Gitfiddle

    Nice article some good information in there. Five or 6 years ago over clockers were a minority but things have changed. And the times change with it. I leave for work with a 31 percent O/C on my CPU. How much do I need it while I am not here ?

    Good job guys :thumb:
  3. Cerberus

    Cerberus Newbie

    Referencing page 3, Step #1 : Turn On EIST, C1E Or Cool'n'Quiet

    "For those who are worried about the spiralling cost of electricity, this tip alone can save you quite a bit of money. Using my overclocked PC as an example, enabling EIST or C1E would save me about 13 megawatts of power a month if I just run the processor at 3.4 GHz without overvolting. When running at full 3.9 GHz, I would save about 26 megawatts a month."

    Power use over time is referred to in watt/hours and typically billed in kilowatt/hours (kw/hr). A savings of 18 watts of power equals .018 kw/hrs. Say the computer is run 24/7 all month.
    31 (days) * 24 (hrs/day) = 744 (hrs/month)
    .018 kw/hrs * 744 hrs = 13.392 kw/hrs

    This would make your "13 megawatts of power a month" actually a 13.392 kw/hr savings and "26 megawatts a month" a 26.784 kw/hr savings.

    Otherwise, a very nice article.
    1 person likes this.
  4. ivybat

    ivybat Newbie

    It's interesting, I never have had problems with these features before either, but everything I hear about them is a horror story. It seems like the multiplier difference you pointed out earlier probably has a lot to do with it: consistent, dramatic increases in clock will probably knock your computer off its feet, if for no other reason than the obscenely fast and huge increase in temperature that results in raising the clock and going to full load at the same time.

    It's nice that people are starting to write green articles more often, if for no other reason than to help us all save a little green.

    Cheers :)
  5. Chai

    Chai Administrator Staff Member

    Yup, I hear nothing but horror stories too. Maybe the CPU is not stable when EIST is turned on, lack of voltage. You can't actually stress test with Prime 95 when EIST is turned on, unless you specifically change the multiplier to 6x and voltage to simulate EIST.

    I tried using EIST when I changed the multiplier from the default 8x, and I couldn't boot into Windows. That could be another reason.

    Anyway you brought up a good point, I will update the article.
  6. Zenphic

    Zenphic Newbie

    I didnt read through the article yet, but undervolting the processor is a very overlooked thing amongst overclockers. Sure you can bump your voltage all the way up 1.5V immediately and be sure that you can overclock really high, but efficiency is a better idea. I myself am running my E2160 at 2.5 Ghz @ 1.06V. That's way lower than the stock voltage and I'm getting a boost in performance. The power savings should be nice.

    CALLOFDUTY05 Newbie

    Nice article Dashken.Will come in handy when OC'ing. :)
  8. jarome

    jarome Newbie

    Not quite right

    Power is billed in kilowatt-hours, not kilowatts/hour
    so the savings is 18 watts * 744 hours/1000, which is 13.392 kilowatt-hours. At 10 cents/kwh, thats a savings of $1.33 a month.You will not get rich on this.

    But it does multiply if you have to use air conditioning to remove the heat.
    1 person likes this.
  9. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Hey guys, yeah, my mistake. It's not megawatts but actually kilowatt-hours. :wall: :wall:

    Thanks for noticing it and letting me know about it. :beer: :beer:

    Correcting it now. +rep to the both of you. :beer:
    Last edited: May 5, 2008
  10. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Actually, I don't think switching to 6x multiplier can simulate EIST. The problem with EIST, if I'm not mistaken, is not the low multiplier but rather the transition from high to low multipliers and back again.
  11. Chai

    Chai Administrator Staff Member

    The transition is pretty stable. The only potential problem with EIST is, from my experience anyway, if you are not using the stock multiplier, EIST might causes crashes. I tried using 8x multiplier instead of 9x, and boot into Windows with EIST enabled, it wouldn't even pass the splash screen.

    If the EIST is turned on, the slower clockspeed and lower voltage is not sufficient for full stability. For example, 3.4GHz at stock voltage, meaning when EIST is on, the processor will also have to be stable at 2.2GHz at just 1.05V.
  12. cherullo

    cherullo Newbie

    Control is the key

    Nice article, I really like this philosophy. I've been underclocking and overclocking my machines for a while now.
    Anyway, I hate this automatic stuff. Automatic means that if it's broken you can't fix it. Be it BIOS-based or OS-based automation, these algorithms must work of every CPU out there, so they are not accurate enough.
    So I turn all this crap off and use external apps that allow me to tweak all the important parameters to my heart's content.
    On AMD platforms I use Crystal'n'Quiet, and on Intel platforms I use RightMark CPU Clock Utility. Both allows multiplier and voltage management on the fly. You create profiles based on CPU load and the program does the rest.
    So, for everyday use, select 2 or 3 multipliers (the minimal, the maximal, and maybe one in between), lower your FSB to, say, 200Mhz, and for every multiplier chosen, discover the lowest voltage that maintains stability. Prime95 works, but make sure you're using a multi-threaded version. Then setup the profiles and be happy. It takes some time to find these voltages, but it pays off because dissipation increases linearly with clock increase, but it's quadratic with voltage increase (ie, 1.1x Freq = 1.1x Dissipation, 1.1xVoltage = 1.21 xDissipation).
    When you're into something more hardcore, close the app, fire up Abit's uGuru and load a kickass overclock-from-hell profile. I don't know about Intel platforms, but in AMD platforms, uGuru allows changing the "FSB" on the fly, so there's no caveat to this scheme.
    On Intel platforms, there is that bizarre throttling that should work, but I don't like it, it really messes my notebook - can't even play a MP3 at 800Mhz :)
    Someone knows how to change the Intel FSB on the fly (without uGuru)?

  13. Lacus

    Lacus Newbie

    Guys, i was wondering...these power saving features, is it based on Motherboard brand and also the bios it uses or it depends on the processor itself? Cause i'm running a X2 5000+ BE and when i OC, the Cool and Quiet Option dissapears :S.
  14. Chai

    Chai Administrator Staff Member

    I agree with most of the things you said, but it's really a hassle to keep changing the profile by yourself. What if you forget about it? I'm sure it will happen to me all the time! :haha:

    Yes, uGuru can be changed on the fly on Intel too, that's why uGuru was mentioned in the article.
    BE? Did you change the multiplier? On my board, if I change the multiplier, the EIST will make Windows crash on boot up!
  15. cherullo

    cherullo Newbie

    These apps change the profile based on CPU load, it's automatic. For example, I'm at 800Mhz right now. If a heavy Flash opens up, my machine will go to 1.8Ghz automatically - the Crystal'n'Quiet does it for me. If I need the extra oomph, firing uGuru will take me to 2.7Ghz, sweet but completely overkill for web/mail/MSN.
    The real work is finding the minimum voltage per frequency.

    Well, firing up uGuru for the max overclock IS a hassle in my machine, because I must remember to shut down Crystal'n'Quiet, set the vCore to it's max and then overclock in uGuru. Missed steps are a sure hang.

    Considering that 40k+ people already read your article, if 5% of this crowd tried to do what I said, you'd certainly be buried forever in e-mails regarding this, hahahahahah!

    Sure, it changes the multiplier. And the FSB/Memory? In theory you could always get to 6x200Mhz = 1.2Ghz minimum, instead of 6x333=2Ghz.

    That sucks big time. I feel like Intel's automatic stuff work perfectly for off-the-shelf equipment, but fiddle a little and it falls apart. But I shouldn't brag, if I set the multiplier to 8.5x my machine goes bananas. Go figure. By the way, it's a 3 years old AMD 939 Venice.
  16. Chai

    Chai Administrator Staff Member

    I tried using RM Clock utility, I don't find it useful, as I'm still limited by the same 6x multiplier and the lowest VID range used by EIST/C1E.

    Then it's definitely much better to use EIST and uGuru combo, because both works very well together.

    Yes, FSB/Memory. But there's a problem with it as well. I couldn't change more than 50MHz at a time. It will crash the system, for example, from 430MHz to 370MHz. There's no multiplier option for Intel I think.

    I can understand why it will go haywire, because by changing the multiplier, you are overwriting the EIST settings. No surprise at all. In fact, it's Windows power option which got confused by it, not the processor/motherboard combo.
  17. ChampionLLY

    ChampionLLY News Writer

    I think that power supply efficiency is important too when it comes to power saving related issues.

    I also have underclocked & undervolted my Q6600 to 1.1v @ 245x9 w/ EIST after realizling that all my games are gpu-limited..
  18. Chai

    Chai Administrator Staff Member

    That is one of the factor to consider. But most PSU reaches good efficiency at above 100W. Even at idle, my system is already hovering 138W.

    I've roughly calculated the potential power saving from 70% to 80% efficiency at 138W DC draw. You can save about 14W. Not that much, but it's "measurable".

    And not forgetting that getting a good PSU costs money. :mrgreen:
  19. slugbug

    slugbug Newbie

    Overclocking and power savings are usually not synonymous with each other, so tips like this can certainly help.
  20. ChampionLLY

    ChampionLLY News Writer

    Hmm, you've got a point there.. I still think its a good investment to get a high efficiency high power psu which will last for years to come..

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