Undervolting: how low can you go?

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jackylman
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Post by jackylman » Wed Jul 18, 2007 3:24 am

Palindroman wrote:
AMD Athlon 64 3500+ - Orleans (AM2)

Minimum: 1.0GHz @ .925V
Stock: 2.2GHz @ 1.150V
What is the stock voltage of this one, do you know? There Orleans-core Athlons with different power envelopes, I believe.
Sorry, but I'm eactly not sure. It's either 1.35 or 1.40. Here is the product page for it on the site where I bought it. It is a Rev. F2, 62W.

jojo4u
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Post by jojo4u » Wed Jul 18, 2007 9:09 am

Palindroman wrote: If I may ask, how come the Meroms don't go below a 0.950v (T5600) and 0.975 (T7400) respectively..
The VID is locked. The specified lower vcore is probably the acceptable range for the package. AFAIK, in order to go lower, one would need BIOS undervolting. You could also mod your VID pins ;)

Palindroman
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Post by Palindroman » Wed Jul 18, 2007 11:30 am

jojo4u wrote:
The VID is locked. The specified lower vcore is probably the acceptable range for the package. AFAIK, in order to go lower, one would need BIOS undervolting. You could also mod your VID pins ;)
Okay, forget I asked. :)



I have a relative new CPU to add (tested it today):

AMD X2 BE-2350 (AM2) stock - 1.25V

Minimum: 1.0 GHz @ 0.825 Volt
Stock: 2.1 GHz @ 1.000 Volt


I haven't tested this thoroughly. I had it running at 0.8v, stress tested it with Orthos for about 10 minutes, all went well, but when a window popped up the system shutdown. Power savings: 2 watts (compared to Cool 'n Quiet), 7 watts compared to normal idle, 12 watts compared to normal peak load.

jojo4u
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Post by jojo4u » Wed Jul 18, 2007 1:23 pm

jojo4u wrote: AFAIK, in order to go lower, one would need BIOS undervolting.
[/quote]

I forgot one thing: When the CPU is in C4 and the BIOS is configured correctly, the voltage should be lower. (Deeper Sleep and Enhanced Deeper Sleep).

jackylman
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Post by jackylman » Wed Jul 18, 2007 4:34 pm

Ok, please ignore my previous entry for the Orleans core. I got to do some troubleshooting on my mom's PC today and it turns out I got the numbers wrong. The CPU performs better than I thought, so let me try it again:

AMD Athlon 64 3500+ - Orleans (AM2) stock - 1.35V (Rev. F2, 62W)

Minimum: 1.0GHz @ .900V
Stock: 2.2GHz @ 1.100V

Palindroman
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Post by Palindroman » Mon Aug 27, 2007 12:40 am

I finally got round to testing an Athlon 3500+ (45W Lima-core).

AMD Athlon 64 3500+ - Lima (AM2) stock - 1.35V

Minimum: 1.0 GHz @ 0.800 Volt
Stock: 2.2 GHz @ 1.025 Volt

Mikael
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Post by Mikael » Mon Aug 27, 2007 7:58 am

Intel Core 2 Duo E6600 - Conroe (S775) stock - 1.2650V

Minimum: Haven't tried
Stock: 2.4 GHz @ 1.000V
OC'd: 3.0 GHz @ 1.175V

Best result yet? 8)

scaryduck
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Location: London, UK

Post by scaryduck » Mon Aug 27, 2007 9:13 am

Intel Core 2 Duo T5600 - Merom S479. Stock 1.1V

Minimum (SpeedStep, 1GHz): 0.85v (lowest possible)
Stock (1.8GHz): 0.87v

Not sure why this processor will accept 0.85v. Got if off eBay as a laptop pull.

vdsl
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Post by vdsl » Mon Aug 27, 2007 1:51 pm

I have Biostar Ta690g + X2 3600+ Brisbane, and lowest stable vcore is 1.1v @ 1000mhz. I just cant understand why i cant go lower :cry:

At first i was trying with stock bios + used winxp, i then flashed to latest bios, and it didnt help. I now formated and installed Winxp and its the same. The strange thing is that when i set in bios 0.950v it work and boot till when it need to start windows, and there it freeze. When i try to underclock in Windows with rmclock or ccid my pc just freeze if i go lower than 1.025v.

What could be the reason for this ? MAybe because i dont have winxp sp2 ? (that is the only thing i didnt tryed)
Im happy with 1.1v but i will be much happier with something lower.

trxman
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Post by trxman » Mon Aug 27, 2007 7:45 pm

jaldridge6 wrote:e6300@ 1.125v 2.4ghz, 400x6, 1600mhz FSB......... stable as stable can be.
soujir0u wrote:C2D E6300 @ 2.8GHz (400 x 7) 1.1625v

48 hours Orthos stable.
people, you've just made my day!

viewtopic.php?t=43035

thx!

this topic should be made sticky! ;)

trxman
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Post by trxman » Mon Aug 27, 2007 7:49 pm

not so actual nor interesting, but here are some of my results:

Athlon64 3000+ Newcastle (s754) default: 1.0GHz @1.1V, 1.8GHz @1.4V and 2.0GHz @1.5V

Image


Athlon64 3000+ Winchester (s939) default: 1.0GHz @1.1V and 1.8GHz @1.4V

Image


:wink:

ddrueding1
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Post by ddrueding1 » Mon Aug 27, 2007 9:07 pm

Intel Pentium M Dothan 1Ghz

Minimum (600Mhz): 0.7v (lowest possible)
Stock (1GHz): 0.748v

This is in my ASUS R2Hv-A1. Using "Notebook Hardware Control", great program.

Originally it ran @ 0.940V @ 1Ghz...a significant improvement!

papakoo
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Post by papakoo » Tue Aug 28, 2007 12:55 am

AMD athlon X2 4200EE windsor 90nm / 65W / AM2

1GHz 0.8V

2.2Ghz stock speed at 1,125V

Steve Teixera
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Post by Steve Teixera » Tue Aug 28, 2007 9:13 am

Intel Pentium M Dothan 1,5 GHz

0,6GHz 0.7v (lowest possible, original 0.988v)
1,5GHz 0.972v (stable at 0.940, I add two VIDs for daily use, original 1.340v)

In my Acer TM290 using "RM Clock"

Intel Pentium M Banias 1,3 GHz

0,6GHz 0.796v (original 0.956v)
1,3GHz 1.180v (original 1.340v)

In my Server using "NHC"

AMD Sempron64 3000+ E6 90nm / 62W / 754

0,8GHz 1.1v (lowest possible, E6 stepping bug)

1,8GHz stock speed 1.15v

2,3GHz OC 1.4v

ryboto
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Post by ryboto » Thu Aug 30, 2007 8:06 am

I just got a Brisbane X2 4000+. Currently it's operating at 2.1ghz with 1.025v, been orthos testing for 10+ hours, hopefully it's still up and running when I get home. Then I'll try for the lowest vcore/multi.

frank2003
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Post by frank2003 » Thu Aug 30, 2007 9:05 am

ryboto wrote:I just got a Brisbane X2 4000+. Currently it's operating at 2.1ghz with 1.025v, been orthos testing for 10+ hours, hopefully it's still up and running when I get home. Then I'll try for the lowest vcore/multi.
Good for you. In my tests, my 4000+ and BE-2350 could run stable only at 1.056 and above. Any voltage lower Orthos errored out in the first 2 minutes.

ryboto
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Post by ryboto » Thu Aug 30, 2007 10:08 am

frank2003 wrote:
ryboto wrote:I just got a Brisbane X2 4000+. Currently it's operating at 2.1ghz with 1.025v, been orthos testing for 10+ hours, hopefully it's still up and running when I get home. Then I'll try for the lowest vcore/multi.
Good for you. In my tests, my 4000+ and BE-2350 could run stable only at 1.056 and above. Any voltage lower Orthos errored out in the first 2 minutes.
well, maybe mine did error out. I had it operating at 1.05v overnight, I only switched it to 1.025v this morning when I woke up. Then I turned my monitor off and left. I know it at least hasn't crashed the pc, since I got the AOL system message when i logged on at work, which means my pc was still on at home. But it at least worked for more than 2 minutes, since I ate breakfast, got lunch ready and then used my pc to check the weather, all the while it was on 1.025v. Hopefully I'll have some time to test it tonight. It's running on a Pico PSU as we speak.

mimwdv
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Post by mimwdv » Thu Aug 30, 2007 7:22 pm

Sempron 3000+
800MHz @ 0.8V (Mobo limited)
1.8GHz @ 1.2V
(Using CrystalCPUID)

e6400
Stock speeds at 1.0V
(bios - I can't get RMClock or CrystalCPUID to work on this system)

ryboto
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Post by ryboto » Fri Aug 31, 2007 5:58 am

So, here are my results,

Athlon X2 4000+ 65W Brisbane

Minimum: 1.0ghz @ 0.856v
Stock: 2.1ghz @ 1.031v

For some reason setting a 4x multiplier in windows using CrystalCPUID causes the system to lock up, but 5x doesn't. Also, I've found that my motherboard overvolts by about 0.006v. Not really much, but you can tell from my results. Those are the numbers CPU-Z reports. The Abit software that came with my motherboard rounds up to the nearest hundredth.

Steve Teixera
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Post by Steve Teixera » Fri Aug 31, 2007 8:56 am

ryboto wrote:For some reason setting a 4x multiplier in windows using CrystalCPUID causes the system to lock up
lowering the HT Multiplier to 4X (800) sometimes fixes this problem

ryboto
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Post by ryboto » Fri Aug 31, 2007 9:04 am

Steve Teixera wrote:
ryboto wrote:For some reason setting a 4x multiplier in windows using CrystalCPUID causes the system to lock up
lowering the HT Multiplier to 4X (800) sometimes fixes this problem
I'll try that. I want to run my Ram at ddr2-800, or closer to it than ddr2-700, which is what the dividers put it at now. So, I was thinking of running an FSB of 210 multiplier of 10, and then I could have the ram operate at ddr2-840. This would of course require me to drop the HT multiplier less than 5x to keep it under 1000mhz.

FlorisNielssen
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Post by FlorisNielssen » Fri Aug 31, 2007 9:50 am

AMD Athlon X2 3800+ (65W, Windsor, AM2, 1.35V)
10x (2 GHz) 0.975V
8x (1.6 GHz) 0.9V
5x (1 GHz) 0.8V

Using Crystal CPUID.
All stable with 24h Prime95 (on both cores).
(Temperatures don't exceed 30C on full load, 10x, with a Arctic Cooling Alpine 7.)


In my laptop:
Intel Core 2 Duo T2500 (details unknown)
12x (2 GHz) 1.1V
6x (1 GHz) 0.95V (stock, because I haven't got the option to put it any lower)

Using Notebook Hardware Control.
Stable with 12h Prime95 (on both cores).
Last edited by FlorisNielssen on Mon Sep 10, 2007 3:59 am, edited 1 time in total.

ryboto
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Post by ryboto » Fri Aug 31, 2007 10:11 am

FlorisNielssen wrote:AMD Athlon X2 3800+ (65W, AM2, 1,35V)
10x (2 GHz) 0.975V
8x (1.6 GHz) 0.9V
5x (1 GHz) 0.8V

Using Crystal CPUID.
All stable with 24h Prime95 (on both cores).
(Temperatures don't exceed 30C on full load, 10x, with a Arctic Cooling Alpine 7.)
that's pretty crazy. That's better than the BE. Are you sure your board is giving exactly the vcore you set it to? I've found that the two boards I've used CrystalCPUID with, they've always slightly over-volted. I can't imagine you see much of a difference in power consumption between those three power states.

merlin
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Post by merlin » Fri Aug 31, 2007 12:31 pm

Core 2 Duo e6600 on Gigabyte P35-DS3R
2.0ghz at .95V
Based on the under 30C temps at idle and under 40C temps at load along with much lower power usage, it's pretty clear this is actually working. If I wanted a really low power system, undervolting/underclocking certainly does the trick with the Core 2 series.

treker
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C2D E6400 Stock 2.13ghz @ 1.01Vc

Post by treker » Sat Sep 01, 2007 7:45 am

Orthos stable at stock 2.13ghz at 1.01V. Doesn't appear to have any Vdroop on this Gigabyte DS3. Everest shows 1.01V at idle and 100% workloaded. Bios setting is 1.05.

I usually run 25% overclock at 1.15V. VID is 1.325V

darkbulb
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Post by darkbulb » Sun Sep 09, 2007 1:27 am

ryboto wrote:So, here are my results,

Athlon X2 4000+ 65W Brisbane

Minimum: 1.0ghz @ 0.856v
Stock: 2.1ghz @ 1.031v
New Athlon X2 4000+ 65W Brisbane user myself.
Minimum: 1 GHz 0.864V
Stock: 2.1 GHz 1.056V

My board also seems to be adding 0.006-0.014 V.
At 2.1GHz, going any lower than 1.05 in RMClock instantly reboots the system.

Also, I cannot understand why anything lower than 1.2 set in BIOS (at 2.1GHz) causes problems. I cannot even start Windows, at 1.15V I hardly could go back to BIOS config after several restarts). However, setting 1.2V in BIOS and further undervolting with RMClock works great. Anyone else seeing this? The board is Asus M2A-VM HDMI , BIOS 0703

fas_k
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Post by fas_k » Mon Sep 10, 2007 2:51 am

darkbulb wrote:
ryboto wrote:So, here are my results,

Athlon X2 4000+ 65W Brisbane

Minimum: 1.0ghz @ 0.856v
Stock: 2.1ghz @ 1.031v
New Athlon X2 4000+ 65W Brisbane user myself.
Minimum: 1 GHz 0.864V
Stock: 2.1 GHz 1.056V

My board also seems to be adding 0.006-0.014 V.
At 2.1GHz, going any lower than 1.05 in RMClock instantly reboots the system.

Also, I cannot understand why anything lower than 1.2 set in BIOS (at 2.1GHz) causes problems. I cannot even start Windows, at 1.15V I hardly could go back to BIOS config after several restarts). However, setting 1.2V in BIOS and further undervolting with RMClock works great. Anyone else seeing this? The board is Asus M2A-VM HDMI , BIOS 0703

hey guys i have a pentium d 945 sl9qq. currently running at 3.4ghz dual core. 200x17x . has anyone tried underclocking this cpu . i want to as me fan is to loud and emps sometinmes go on the high side.
if anyone has please let me know with vcore figs and fsb.

FlorisNielssen
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Post by FlorisNielssen » Mon Sep 10, 2007 3:51 am

ryboto wrote:
FlorisNielssen wrote:AMD Athlon X2 3800+ (65W, AM2, 1,35V)
10x (2 GHz) 0.975V
8x (1.6 GHz) 0.9V
5x (1 GHz) 0.8V

Using Crystal CPUID.
All stable with 24h Prime95 (on both cores).
(Temperatures don't exceed 30C on full load, 10x, with a Arctic Cooling Alpine 7.)
that's pretty crazy. That's better than the BE. Are you sure your board is giving exactly the vcore you set it to? I've found that the two boards I've used CrystalCPUID with, they've always slightly over-volted. I can't imagine you see much of a difference in power consumption between those three power states.
It sure is low, yes. I was surprised too. Was hoping for 1.1V for 10x (which was standard for 5x) and 0.8-0.9V for 5x.
That's why I tested it a whole day to check if it really was stable.
I suppose the Vcore is good, looked with CPU-z and it seemed fine. Can I check it better with something?
I haven't checked with power consumption, I don't have something here to measure it with.

Edit: just checked my Vcore, 0.8V seems to be 0.816V, 0.975V seems to be 0.976V. (With CPU-z.)

Flandry
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Post by Flandry » Mon Sep 10, 2007 4:02 am

Intel Pentium M Dothan 1.7 GHz (Intel Pentium M 735)

0.6 GHz 0.7 V (lowest possible, original 0.988v?)
1.7GHz 1.004 V

I keep it limited to 1.4 GHz @ 0.908 V because i don't really need the extra 300 MHz or the extra heat when i'm gaming.

It's amazing to me how incredibly low a voltage this 3-4 year old processor needs. According the battery current circuitry, at idle the whole laptop consumes less than 12 W.

Until i get my C2D system, my only desktop results to share are:

Intel Pentium III-S (Tualatin) 1.26 GHz

Design power of 30.4 W power, 3.6 W less than the 1.68 GHz Intel Core 2 Duo T5500 (Merom) and 7.4 W more than the above Pentium M at stock.

1.36 GHz (142 MHz FSB) @ 1.45 V (stock Voltage not adjustable on my mobo, processor multi is locked :/)

With two of these suckers on the board and a couple SCSI HDs, i can see why i can't get the system idle below 130 W.

fas_k
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Post by fas_k » Mon Sep 10, 2007 4:42 am

Anyone underclocked a pentoum d 945 if so please show clock settings.
vcore settings etc. fsb etc. !!!!!!!!!!!!

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