Reducing The Power Consumption Of Overclocked PCs

[Chai]

Originally Posted by Adrian Wong

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.

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.

[cherullo]

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)?

Cheers

[Lacus]

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.

[Chai]

Originally Posted by cherullo

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)?

Cheers

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!

Yes, uGuru can be changed on the fly on Intel too, that's why uGuru was mentioned in the article.

Originally Posted by Lacus

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.

BE? Did you change the multiplier? On my board, if I change the multiplier, the EIST will make Windows crash on boot up!

[cherullo]

Originally Posted by Chai

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!

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!

Originally Posted by Chai

Yes, uGuru can be changed on the fly on Intel too, that's why uGuru was mentioned in the article.

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

Originally Posted by Chai

BE? Did you change the multiplier? On my board, if I change the multiplier, the EIST will make Windows crash on boot up!

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.

[Chai]

Originally Posted by cherullo

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.

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.

[ChampionLLY]

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..

[Chai]

Originally Posted by ChampionLLY

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..

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.

[slugbug]

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

[ChampionLLY]

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..