It is currently Mon Sep 22, 2014 10:44 pm

All times are UTC - 8 hours




Post new topic Reply to topic  [ 23 posts ] 
Author Message
 Post subject: Has anybody tried undervolting sandybridge yet?
PostPosted: Mon Jan 10, 2011 10:02 pm 
Offline

Joined: Tue Apr 25, 2006 8:46 am
Posts: 51
Location: Scotland
Hi. Im interested in knowing how well desktop sandybridge (i5-2500k,i7-2600k) undervolt at stock speeds, and lower frequences. Has anybody tried it yet?......cheers.

_________________
Viewsonic VP930 Lcd, Thermaltake (Black) Armor Case, A7N8X-E Deluxe, 2500XP Barton, Thermalright SI-97 With 92mm Vantec Tornado Fan, 1Gb Patriot PC3200 Dual Channel Low Latency Ram, Sapphire Radeon 9800SE (256bit), Zalman ZM80D-HP Gpu Cooler With ZM-OP1 80mm Fan, 250Gb Seagate Barracuda 7200.8 SATA NCQ, Pioneer DVR-109 dvd-r.


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Tue Jan 11, 2011 11:55 am 
Offline

Joined: Wed Feb 28, 2007 4:55 pm
Posts: 33
I just ordered my 2500K with a P series motherboard and the very first thing I will do with it is see how low it can go at stock speed. I will post detailed results on the forum in the style of my MSI 5770 review.


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Tue Jan 11, 2011 3:26 pm 
Offline
Patron of SPCR

Joined: Fri Dec 27, 2002 1:49 pm
Posts: 835
Location: Somerset, WI - USA
Sandy Bridge, Part 2: Intel DH67BL & Asus P8H67-M EVO H67 Motherboards

SPCRs review included the Asus board where the EPU utility undervolts the CPU by about 0.05V at idle and 0.8V under load. I would guess that you can probably undervolt more. But like withe the Clarkdale CPUs, there's little to no change in idle power. The modest undervolt did help bring the load power down by about 4W on the lower powered CPU and 8W on the higher clocked one.


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Fri Jan 14, 2011 6:17 am 
Offline

Joined: Tue Apr 25, 2006 8:46 am
Posts: 51
Location: Scotland
silentplummet wrote:
I just ordered my 2500K with a P series motherboard and the very first thing I will do with it is see how low it can go at stock speed. I will post detailed results on the forum in the style of my MSI 5770 review.


Thats great...thanks

_________________
Viewsonic VP930 Lcd, Thermaltake (Black) Armor Case, A7N8X-E Deluxe, 2500XP Barton, Thermalright SI-97 With 92mm Vantec Tornado Fan, 1Gb Patriot PC3200 Dual Channel Low Latency Ram, Sapphire Radeon 9800SE (256bit), Zalman ZM80D-HP Gpu Cooler With ZM-OP1 80mm Fan, 250Gb Seagate Barracuda 7200.8 SATA NCQ, Pioneer DVR-109 dvd-r.


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Fri Jan 14, 2011 6:36 am 
Offline

Joined: Tue Apr 25, 2006 8:46 am
Posts: 51
Location: Scotland
BillyBuerger wrote:
Sandy Bridge, Part 2: Intel DH67BL & Asus P8H67-M EVO H67 Motherboards

SPCRs review included the Asus board where the EPU utility undervolts the CPU by about 0.05V at idle and 0.8V under load. I would guess that you can probably undervolt more. But like withe the Clarkdale CPUs, there's little to no change in idle power. The modest undervolt did help bring the load power down by about 4W on the lower powered CPU and 8W on the higher clocked one.



yeh...im hoping they can be undervolted to use no more than 1.0v under load at stock speed.....looks promising.

_________________
Viewsonic VP930 Lcd, Thermaltake (Black) Armor Case, A7N8X-E Deluxe, 2500XP Barton, Thermalright SI-97 With 92mm Vantec Tornado Fan, 1Gb Patriot PC3200 Dual Channel Low Latency Ram, Sapphire Radeon 9800SE (256bit), Zalman ZM80D-HP Gpu Cooler With ZM-OP1 80mm Fan, 250Gb Seagate Barracuda 7200.8 SATA NCQ, Pioneer DVR-109 dvd-r.


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Fri Jan 14, 2011 4:29 pm 
Offline

Joined: Wed Feb 28, 2007 4:55 pm
Posts: 33
OK, I just got my i5-2500k setup with Asus p8p67 PRO mobo. I've got prime95 running on all four cores. CPU-Z reports 3400 MHz, Speedfan reports 1.03V (set 1.09 in bios) and cores currently at 44 C. I have this on a Prolimatech megahalems with no fan so I expect it to max out a few degrees hotter with enough time.

We'll see how hot it ultimately gets and whether it can sustain a whole night of prime95, but my initial impression is that this already far exceeded my expectations. If it gets through a few more hours of prime95 with no error I'll undervolt some more.

Edit @ 7:47 PM, a few minutes later and we seem to have maxed at 48 C. Cores 0/1 are about a degree cooler than cores 2/3. All I can say is holy shit, do I have a golden sample? This thing is producing at least 220% of the raw compute performance of my E8400 with even lower thermals. And this is supposed to be 95W TDP versus the E8400's 65W?? I get the feeling I haven't even approached rock bottom voltages yet.


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Sat Jan 15, 2011 6:47 am 
Offline

Joined: Wed Nov 22, 2006 8:44 am
Posts: 30
maybe you guys can help me to clear things up a bit. I got a 2500K and an Asus P8p67. In the Bios I enabled EPU and there is also the Offset Option. If I understand that correct then offset is the new way to Undervolt right? It determines the voltage difference regardless if the CPU is in idle or full load.
So I just enable EPU and for further undervolting I experiment with the Offset to see how much I can push there?

edit: this is what looks stable so far. EPU on Auto, Offset to -0.09V. Prime 95 large FFTs test (don't know if this is the right one) 52° (from CPUID HWMonitor)@1.024V (from CPUZ) cooled by a Megahalem with a Scythe Slipstream@5V

edit2: @Silentplummet: which tool did you use to meassure temps? If it was speedfan only the beta version 443 show the correct temps. 442 will display 10 degrees less than it is (on my P8P67 at least).


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Sun Jan 16, 2011 5:57 am 
Offline

Joined: Thu Mar 13, 2008 5:56 am
Posts: 198
Location: Estonia
Here these guys did some undervolting
http://www.computerbase.de/artikel/proz ... dervolting
(in german)

_________________
#6) Plug in one device at a time, stick your fingers in your ears, close your eyes, and hit the power switch with a toe


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Mon Jan 17, 2011 6:13 am 
Offline

Joined: Wed Feb 28, 2007 4:55 pm
Posts: 33
Souli wrote:
If it was speedfan only the beta version 443 show the correct temps. 442 will display 10 degrees less than it is (on my P8P67 at least).


Thanks so much for this tip, I knew something had to be up but I had no reason to distrust what speedfan was telling me! It turns out I had been hitting around 61 C and not 48 C as shown. Not dangerous temperatures but still too hot for my liking.

I broke down and relocated a superfluous Noctua 800 RPM fan from the drive bay to the Megahalems (paradoxically, this reduced the noise it produces to nearly undetectable levels even at max RPM). This change and the minimum stable voltage I reached of 1.065 V (bios)/ 1.000 V (after vdroop in 4 core prime95 load conditions) brought the load temps down to 41 C max, confirmed by the speedfan beta and the recently released 2.6.36 Linux kernel. Now 41 C and blessed quiet I can live with.

Now begins the tedious scientific process of finding minimum stable voltages at various multiplier and turbo settings. I'm not sure exactly how to go about this as the motherboard offers so much flexibility. The turbo function adds yet another dimension to the testing. Apparently the turbo function at factory settings scales with the number of loaded cores. Max turbo on the i5-2500 is 3700 MHz but it will only attempt this with 1 core loaded. When you load all four cores it scales them down to 3400 MHz. Unfortunately the motherboard allows you to set only a base voltage and then an extra voltage offset for when turbo is enabled. This means you have to find a single voltage (base + turbo extra) stable over the entire range of turbo states.

It seems you can artificially limit the range so that under 1-core load conditions the turbo frequency target is the same as for fully loaded conditions, but this is untested and theoretical for me at this point. There are many settings in the BIOS related to turbo function and honestly I have no idea how any of them work in practice. The details given in the online help are characteristically unhelpful.


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Tue Jan 18, 2011 1:43 pm 
Offline

Joined: Wed Feb 28, 2007 4:55 pm
Posts: 33
Update. Right now I'm folding at 4 GHz on the SMP core in amd64 linux. I set the voltage to 1.275 but have no means of checking Vdroop in linux. Average core temp is 57 C with the 800 RPM noctua fan I slapped on it. I think there is still some headroom with the voltage but probably not too much. The same setting was on the threshold of stability at 4.2 GHz. Will tinker some but I think I'm going to stick with ~4 GHz for my target settings. Can't beat the silence and the thermals aren't TOO bad. I'd like to get them under 55.


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Thu Jan 20, 2011 12:45 pm 
Offline

Joined: Thu Dec 02, 2010 11:39 pm
Posts: 41
If they can be undervolted so well, is there any point in buying the expensive 2390 or T/S versions of the CPUs? Might as well get a 2500K on Z68 with overclock potential and better GPU, right?


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Mon Jan 24, 2011 10:11 pm 
Offline

Joined: Tue Apr 25, 2006 8:46 am
Posts: 51
Location: Scotland
jamotide wrote:
If they can be undervolted so well, is there any point in buying the expensive 2390 or T/S versions of the CPUs? Might as well get a 2500K on Z68 with overclock potential and better GPU, right?


I agree with you...plus you have the choice of increasing clocks and volts in the future, to keep up with software.

_________________
Viewsonic VP930 Lcd, Thermaltake (Black) Armor Case, A7N8X-E Deluxe, 2500XP Barton, Thermalright SI-97 With 92mm Vantec Tornado Fan, 1Gb Patriot PC3200 Dual Channel Low Latency Ram, Sapphire Radeon 9800SE (256bit), Zalman ZM80D-HP Gpu Cooler With ZM-OP1 80mm Fan, 250Gb Seagate Barracuda 7200.8 SATA NCQ, Pioneer DVR-109 dvd-r.


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Tue Jan 25, 2011 11:40 am 
Offline
Moderator

Joined: Thu Oct 06, 2005 4:36 am
Posts: 4617
Location: Monterey Bay, CA
jamotide wrote:
If they can be undervolted so well, is there any point in buying the expensive 2390 or T/S versions of the CPUs? Might as well get a 2500K on Z68 with overclock potential and better GPU, right?


+1

_________________
1080p Gaming build: i5-4670K, Mugen 4, MSI Z87-G45, MSI GTX 760 2GB Gaming, 8GB 1866 RAM, Samsung Evo 250GB, WD Red 2TB, Samsung DVD burner, Fractal Define R4, Antec True Quiet 140 (2 front + rear) case fans, Seasonic X-560. 35-40W idle, 45-55W video streaming, 170-200W WoW, 200-230W Rift, 318W stress test (Prime95 + Furmark)


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Thu Jan 27, 2011 5:44 am 
Offline

Joined: Sun Oct 31, 2010 2:51 am
Posts: 16
I'm interested about this Sb cpu's. First i look S or T versions. But after reading this
http://www.xbitlabs.com/articles/cpu/di ... 00s_6.html
and this http://www.silentpcreview.com/article1143-page5.html
review i give priority to non expensive S or T cpu's.

Undervolting i can make alone too, question is only:
How consumption is your SB system? I mean whole system with cpu+ddr3+hdd+psu.

System i'm thinking about:
GIGABYTE Intel H67 + I5 2300.

_________________
*Hate FSP group - company of lie* 250w Psu's from 80plus.org never at market ( test presamples).


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Fri Jan 28, 2011 1:30 pm 
Offline

Joined: Tue Jun 10, 2008 4:57 am
Posts: 20
Location: Sweden
I have undervolted my i5 2400.

Runs on 1.025V (~1.2 V stock) in full load. Temps are *very* low (especially in idle, around 5 C over ambient using Scythe Shuriken mounted with Thermalright Bolt-through kit).

Fan runs in 600-1100 rpm (100 mm fan) which is virtually silent. :D


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Thu Feb 03, 2011 11:55 am 
Offline

Joined: Sun Oct 31, 2010 2:51 am
Posts: 16
Do you tried measure power consumption system with and without undervolted cpu?

I'm so interesting about I5-2500 K with min. undervolting-underclocking points.

_________________
*Hate FSP group - company of lie* 250w Psu's from 80plus.org never at market ( test presamples).


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Thu Feb 03, 2011 1:19 pm 
Offline

Joined: Thu Feb 04, 2010 6:06 pm
Posts: 3395
Location: US
erilun wrote:
I have undervolted my i5 2400.
It idles at under 4 watts. So what is the benefit of undervolting it? It undervolts and underclocks itself, automatically.

In either case (undervolted or not undervolted) it will ramp up if you put a load on it and in any realistic situation that load won't tax it even 50%. In either circumstance it will use the same wattage... just enough to process the load... then return to idle. Right?

_________________
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
"Aristotle calls man the rational animal. All my life I have been seeking evidence to confirm this" Bertrand Russell
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former" Albert Einstein


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Fri Feb 04, 2011 6:57 am 
Offline

Joined: Wed Feb 28, 2007 4:55 pm
Posts: 33
ces wrote:
It idles at under 4 watts. So what is the benefit of undervolting it? It undervolts and underclocks itself, automatically.

In either case (undervolted or not undervolted) it will ramp up if you put a load on it and in any realistic situation that load won't tax it even 50%. In either circumstance it will use the same wattage... just enough to process the load... then return to idle. Right?


So many flaws in your reasoning. Maybe some of us have usage patterns that don't fit the parameters of what you just described?

I run mine flat out, 400% load 24/7. Protein folding simulation for the SPCR F@H team. Moreover, this being SPCR and not HotHardware or HardOCP, I have an obsession with silence. I want to ensure that load temps don't exceed 45C* under ANY load for ANY period of time, and I want to do so while avoiding any cooling solution that would compromise the peace and quiet of my den.

(*achievable at stock frequency by undervolting. In reality my target max temp is 55C but I run at 4 GHz)

Also please realize that wattage (electrical power consumed) and processing power are not correlated. I could run my CPU at 3 GHz@1.0 volts or at 3 GHz@1.5 volts. 'Processing the load' will take exactly the same amount of time in both scenarios. One consumes 50% more power to do so.

The idea is to run the hardware as efficiently as possible by finding the minimum stable voltage at any given clock frequency. That's what we do when overclocking; when we do it at stock frequency we just call it a different name, "undervolting".

Moreover, 'minimum stable voltage' vs. 'clock frequency' is not linear. It is typically an exponential curve. Clock frequency vs. processing time is (ideally) linear. Therefore, given a CPU always running at minimum stable voltage, you will use more power for a given load the faster you try to complete it.

Basically you are wrong on about 3 levels.


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Mon Feb 14, 2011 4:20 pm 
Offline

Joined: Wed Feb 28, 2007 4:55 pm
Posts: 33
Brief update on my SB performance / silence quest. I now achieved 4.5 GHz/ 1.28 V (load; 1.32 bios LLC high). Core temps are at 61 C (ambient 25 C) as I fold on the Linux SMP client. My system is now what I would call 'whisper quiet' whereas it was silent before... here's what I did:

1. Lap CPU and heatsink (megahalems) down to the copper, voiding over 9000 warranties
2. Polish with 1-micron honing compound to a mirror finish
3. IC Diamond TIM
4. 2x Scythe slipstream fans @ 720 RPM push-pull on HSF, case fans are 2x Noctua NF-P12 @ 810 RPM, 1x Nexus Real Silent @ 740 RPM

It's a lot of work (took me probably 5 hours total and ~$80 of equipment) but I managed to shave off 8-10C core and bring the temps down into the region I consider 24/7 safe (<65C).

This is a lot of performance for such a quiet system. SB exceeded my expectation in every way. I thought it couldn't get any better than my Core 2 E8400 :lol:

11th hour update: 4.5 GHz isn't really 24/7 stable on my chip for folding. My chip hits the point of diminishing returns around 4.3 and I wasn't comfortable pushing the volts or thermals high enough for real stability at 4.5. I backed it down to 4.3 for 24/7 OC and real silence :D


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Mon Sep 05, 2011 1:47 pm 
Offline

Joined: Thu Mar 31, 2011 5:04 am
Posts: 14
Location: Finland
Old thread but let's bump it anyway :D

Was doing some experimenting with the voltage on my 2500K last night.
Dropped clocks to 40x100 and started lowering the voltage.
1.152v at 4Ghz :mrgreen:

Dunno if that's good or good but I like it. It was Prime95 stable with 1792k FFT with 4096mb mem load, good enough for me :D
Didn't go any lower yet, gonna try soon though, gotta just do some things first.


Have you guys undervolted your SB's more?
Imma see if I could go 1.1v with 4Ghz :mrgreen:

_________________
HTPC: Intel DH77EB | Intel Pentium G2120+NH-U12P w/o fan | HD5670 w/ Accelero S1r2 | SS-400FL V2 | 8GB DDR3 1600 CL9 1.35v | Lian Li PC-A05N+Slip Stream ~300rpm+Gentle Typhoon ~600rpm | Samsung 830 64GB | WD1001FALS
Work: Asus MIVGZ | 3770K@4.5Ghz/~1.2v | XFX HD5750 | SS-660XP2 | 8GB DDR3 2000 CL10 1.35v | Lian Li PC-A05N+X-Silent 140+2xSS 120 PWM | Intel 520 60GB | WD30EFRX&2x1TB RAID


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Mon Sep 05, 2011 9:56 pm 
Offline

Joined: Wed Aug 10, 2011 3:12 am
Posts: 17
topic may be old but really interesting!

i'm especially interested in findings about a 2500k at (most probably) stock speeds, I'd like to undervolt it to "silence" it as much as possibile; what are your "best" parameters?

I'm going to buy the 2500k for the ability to fine tune its performance to the use, but most of the time I'd like for it to be "dead quiet at full load". It will be provided with a shuriken.

since I'm probably going to use a z68 board (asrock pro3-m) I'd be interested in integrated gpu downvolting also, to bring the heat down as much as possible.


thanks a lot!!


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Tue Sep 06, 2011 7:40 am 
Offline

Joined: Thu Sep 07, 2006 11:20 pm
Posts: 859
Location: Poland
I5 2400 OCed to 3.6 GHz on all cores (4 bins for 400 MHz + 100 MHz Turbo Boost) idles at < 0.8 V and works under load at 1.1 V. Naturally, the board increased Vcore when I increased the multiplier, but I used the available offset (- 0.200 V) to bring it down. This is on a GA-P67A-UD3-B3 board. Perhaps other boards have higher negative/positive offsets available. Still, 0.792 V @ 1600 MHz is not bad. I was initially hoping to get 2500K but either I wouldn't OC it heavily, but rather undervolt it and have it at around 4-4.2 GHz perhaps. Now, with the 3,6 GHz on 2400 I guess I'd rather save up for IB.


Top
 Profile  
 
 Post subject: Re: Has anybody tried undervolting sandybridge yet?
PostPosted: Tue Sep 06, 2011 5:38 pm 
Offline

Joined: Sun Aug 26, 2007 5:03 pm
Posts: 132
Location: eu
Image

2500K stock consumes around 81 Watts, at 3.4Ghz 1.200V

According to this formula: 80W/(1.200*1.200)(1.050*1.050)~60W

At 1.050V it should be 20 watts lower, down to 60Watts As the load in Games and rendering would result even less impact to be only 10 Watts lower with undervolting. is it worth it? I'm stuck with non undervolting motherboard.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 23 posts ] 

All times are UTC - 8 hours


Who is online

Users browsing this forum: Bing [Bot] and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group