Sandy Bridge + i3-2100T -- why can't I get under 22w idle?

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wumpus
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Sandy Bridge + i3-2100T -- why can't I get under 22w idle?

Post by wumpus » Sat Apr 02, 2011 8:55 pm

Based on the (excellent!) Missing Remote review of the i3-2100T:

http://www.missingremote.com/review/int ... otherboard

I built my own low-power Sandy Bridge HTPC based on the i3-2100T:

http://www.codinghorror.com/blog/2011/0 ... er-pc.html

However, (assuming I am reading the MR review correctly) he got an astonishing 14.5w at idle!

Image

I am getting more like 22w idle:

Image

(I also get around 55w prime95 fully loaded peak, and 30w-35w "typical" for web browsing and watching 720p videos.)

The key differences between our builds:

- different mobos (he used Intel Mini-ITX, I used ASRock Mini-ITX)
- different PSUs (he used a PicoPSU, I used Seasonic ECO 300w 80+ purchased from our very own Mike Chin back in the day!)

I guess hard drives + blu-ray drive are a variable, too, but I can't imagine those at idle taking more than 1-2w, as I use generic 2.5" laptop hard drives in my HTPC.

So.. what gives? Can efficiencies in the PicoPSU and Intel Mobo explain the nearly 8 watt difference in our idle power consumption?

ces
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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by ces » Sat Apr 02, 2011 9:10 pm

wumpus wrote:he used Intel Mini-ITX, I used ASRock Mini-ITX
The intel is probably good for a few watts of the difference... as is the PicoPSU.

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by mentawl » Sun Apr 03, 2011 4:51 am

wumpus wrote:So.. what gives? Can efficiencies in the PicoPSU and Intel Mobo explain the nearly 8 watt difference in our idle power consumption?
Absolutely! Some of the newer Intel motherboards are truly exemplary when it comes to idle power consumption, and I wouldn't expect an Asrock to keep up in terms of efficiency.

In terms of the PSU, while the Seasonic may be 80+, this only specifies that the PSU must have 80+ or greater efficiency at 20%/50%/100% of rated load. As 22watts is only ~ 7.5% of the Seasonic's max load, it's entirely possible that efficiency has dropped substantially. A Pico-PSU, on the other hand, will generally maintain 80%+ efficiency down to a really low load, although it's also dependant on the power brick used. Certainly, switching to a Pico-PSU would be likely to improve idle power consumption. For comparison, my Atom-based server with 2 3.5" HDDs and a 2.5" takes ~ 40w idling using a cheapo-nasty Coolermaster 400w PSU, while it's down to ~ 30w using my 90w Pico-PSU.

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by ntavlas » Sun Apr 03, 2011 7:26 am

Ces and Mentawl have pretty much covered the subject. It`s hard to reach the efficiency of a pico psu at such low loads. To put things into perspective lets compare it to the most efficient sff psu that I`ve managed to find at retail. It`s a 80+ bronze fsp rated at 250 watts. That means that it should be at least 82% efficient when the output is 50 watts (20% of the rating) but still struggling to reach 80% efficiency @ 20 watts. A silver or gold rated psu might fare better though at this point it would end up costing as nearly much as the pico psu. As for the performance of the pico psu, it does indeed depend a great deal on the power adapter used, especially since the 12v line regulation depends almost entirely on the power brick.

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by wumpus » Sun Apr 03, 2011 7:52 pm

OK, sounds like the PicoPSU is the way to go here, since I don't feel like swapping the motherboard... yet.

Question #1: the motherboard has both 24-pin and 4-pin power connectors. The PicoPSU does not provide a 4-pin power connector; is it OK / safe / acceptable to leave the 4-pin power connector on the Mini-ITX motherboard unconnected?

Image

Question #2: What power brick should I get if I need really good efficiency at around 15-30w?

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by tim851 » Sun Apr 03, 2011 11:25 pm

wumpus wrote:Question #1: the motherboard has both 24-pin and 4-pin power connectors. The PicoPSU does not provide a 4-pin power connector; is it OK / safe / acceptable to leave the 4-pin power connector on the Mini-ITX motherboard unconnected?
No. The CPU gets powered by that 4-pin connector. You have to connect it. There are adapter cables for that. Newer PicoPSUs come with an ATX12V plug. In your place, I'd get one of these (150XT or 160XT).

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by loimlo » Mon Apr 04, 2011 6:02 am

I'd like to specify one thing -- Missing Remote review didn't specify whether 14.5W is AC or DC draw. If it were AC draw, it's too good to be true. Better than my notebook! :o

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by MikeC » Tue Apr 05, 2011 6:39 am

wumpus wrote:However, (assuming I am reading the MR review correctly) he got an astonishing 14.5w at idle!

Image

I am getting more like 22w idle:

Image

(I also get around 55w prime95 fully loaded peak, and 30w-35w "typical" for web browsing and watching 720p videos.)

The key differences between our builds:

- different mobos (he used Intel Mini-ITX, I used ASRock Mini-ITX)
- different PSUs (he used a PicoPSU, I used Seasonic ECO 300w 80+ purchased from our very own Mike Chin back in the day!)

I guess hard drives + blu-ray drive are a variable, too, but I can't imagine those at idle taking more than 1-2w, as I use generic 2.5" laptop hard drives in my HTPC.

So.. what gives? Can efficiencies in the PicoPSU and Intel Mobo explain the nearly 8 watt difference in our idle power consumption?
Yes, probably. Intel boards generally have the lowest power profile. At such low power levels, the old 300w 80+ cannot be running any better than maybe 65%. Maybe less. A decent 60~80W AC/12VDC adapter can reach around 90% efficiency and, even if it drops to 70% at 10W, it will be better than any 300w 80+ unit w/ multiple voltage rails. The difference will show up at <20W loads.

On the other hand, KaW power meters are not infallible; accuracy wanes at very low power levels. Yours might be giving you too high a reading... though I think the other system would pull a bit less less from the wall anyway.

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by quest_for_silence » Tue Apr 05, 2011 1:44 pm

loimlo wrote:I'd like to specify one thing -- Missing Remote review didn't specify whether 14.5W is AC or DC draw. If it were AC draw, it's too good to be true. Better than my notebook! :o

Code: Select all

The power numbers were measured at the wall with a P3 P4460 Kill A Watt, so they are not DC values.

Let me know if you have any other questions.

Cheers

Andrew Van Til
Senior Editor
MissingRemote.com

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by ilovejedd » Tue Apr 05, 2011 3:35 pm

loimlo wrote:I'd like to specify one thing -- Missing Remote review didn't specify whether 14.5W is AC or DC draw. If it were AC draw, it's too good to be true. Better than my notebook! :o
From this, I'm inclined to think it's the former (AC). As mentioned in another SPCR article, Intel motherboards are partially powered by fairy dust. :P

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by quest_for_silence » Tue Apr 05, 2011 9:42 pm

ilovejedd wrote:From this, I'm inclined to think it's the former (AC).

They explicitly declare it's AC and you're just inclined to think it's AC because of another site? Somewhat hilarious. :idea:

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by ilovejedd » Wed Apr 06, 2011 5:51 am

quest_for_silence wrote:They explicitly declare it's AC and you're just inclined to think it's AC because of another site? Somewhat hilarious. :idea:
I didn't notice the statement where they say it's AC. Had my reply written before your post. Just left the desk and wasn't able to submit it until later.

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by wumpus » Mon May 02, 2011 2:32 pm

Yes, probably. Intel boards generally have the lowest power profile. At such low power levels, the old 300w 80+ cannot be running any better than maybe 65%. Maybe less. A decent 60~80W AC/12VDC adapter can reach around 90% efficiency and, even if it drops to 70% at 10W, it will be better than any 300w 80+ unit w/ multiple voltage rails. The difference will show up at <20W loads.
Well, I went ahead and upgraded to a PicoPSU, specifically this model:

Image

http://www.amazon.com/PicoPSU-90-Adapte ... B0035UETHW

It even includes the 4-pin power connector and it works great! System booted up first time with it connected. However, much to my dismay I am only seeing a drop from 22w at idle to 17w at idle.

Did I get the wrong picoPSU / power brick, or is my ASRock mobo just really that power inefficient?

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by HFat » Mon May 02, 2011 2:57 pm

18W is pretty low if you ask me. You're not using mobile gear!

What's the error in your measurement and the measurement of the people you're comparing your power consumption to? The difference could simply be spurious.
It wouldn't surprise me if your board consumed a couple more watts more at idle. There's also the matter of BIOS settings, drives, RAM and so on.
You'd have to look at this stuff real carefully to explain 3 watts out of 18.

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by ntavlas » Tue May 03, 2011 1:53 am

Did I get the wrong picoPSU / power brick, or is my ASRock mobo just really that power inefficient?
I wouldn`t describe a motherboard that needs 2,5 watts more than the spartan dh67 that inefficient. 17 watts is still an excellent result.

It might be worth looking at the bios settings, disabling some uneeded features here and there might save you an watt or two. You could also try undervolting the cpu. Even though it wouldn`t provide much of a benefit when idle you might see a small improvement at load (5 watts ?).

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by andymcca » Tue May 03, 2011 4:31 am

So those missingremote power figures are AC in? Wow.

This all looks very attractive. What are the specs of your build besides the already-stated cpu/mobo? (specifically, what is the boot media?)

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by olafo » Tue May 03, 2011 8:01 am

wumpus wrote:
Yes, probably. Intel boards generally have the lowest power profile. At such low power levels, the old 300w 80+ cannot be running any better than maybe 65%. Maybe less. A decent 60~80W AC/12VDC adapter can reach around 90% efficiency and, even if it drops to 70% at 10W, it will be better than any 300w 80+ unit w/ multiple voltage rails. The difference will show up at <20W loads.
Well, I went ahead and upgraded to a PicoPSU, specifically this model:

Image

http://www.amazon.com/PicoPSU-90-Adapte ... B0035UETHW

It even includes the 4-pin power connector and it works great! System booted up first time with it connected. However, much to my dismay I am only seeing a drop from 22w at idle to 17w at idle.

Did I get the wrong picoPSU / power brick, or is my ASRock mobo just really that power inefficient?
I think I found the answer to your question. Look at the fact that in the test from missing remote they used only 2GB of RAM - one module, you use 4GB RAM - two modules. That's why there is a diffrence imho. Maybe the mobo also plays some role, I read many reviews of mobos in which intel motherboards beat others when it comes to power consumption but I think that this situation mainly follows that intel motherboards usually don't have additional external controllers like sata, usb etc.

Look also at that test:

http://forums.vr-zone.com/hardware-depo ... ition.html

As you can see, that guy got similar results to yours with normal psu.

BTW 17W in idle it is an excellent result ! :shock: I would like to built similar system but I'm going to wait for the ivy bridge platform.

Sorry if I made some language mistakes, I'm not from english speaking country :wink:

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by ame » Tue May 03, 2011 8:11 am

Wow 17W is super low. Amazing how low these chips go.

Only 3W diff could be anything. I see original review used a single SSD while you are using HDD (and BR drive idle ~0W). Still, that explains ~ 2-3 W gap.

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by wumpus » Tue May 03, 2011 2:34 pm

As you can see, that guy got similar results to yours with normal psu.
Startlingly similar.. 22w idle for different mobo, same CPU, 4 GB.
Only 3W diff could be anything. I see original review used a single SSD while you are using HDD (and BR drive idle ~0W). Still, that explains ~ 2-3 W gap.
Yeah, that plus the only 2GB (versus the 4GB I used).. so you guys are right, 14.5 w idle versus 17w idle is only 2.5 w difference, I probably shouldn't be fretting over it.

It is good to know that in a < 30 w low power system of this type, you really do want a PicoPSU since that resulted in 20% reduction in idle power consumption for me, even over the decent 80 Plus PSU that was in there.
This all looks very attractive. What are the specs of your build besides the already-stated cpu/mobo? (specifically, what is the boot media?)
500 GB hybrid Momentus XT 2.5" drive is the boot / live torrent 24-7 drive -- there are also two 1 TB 2.5" drives for media storage but they should be asleep most of the time.

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by leem » Fri May 06, 2011 11:28 pm

Thanks for this, just the info I needed.

There have been similar posts around the energy efficiency of Intel boards particularly, although MSI boards are also pretty good. I have the ECS socket 1156 board, which compares well with the Intel Socket 1156 board, I don't know how good the other ECS boards are.

These experiences show that the choice of motherboard is becoming a key factor if you are seeking energy-efficient systems, rather than the chipsets or other components.

I've found that the 90W Pico PSU is more than adequate for a 1156 system with four drives, with plenty to spare for a TV card, so should be fine for your 1155 system.

:)

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by salvanos » Sun May 08, 2011 12:34 am

maybe you got lower watt using pico PSU cause seasonic PSU got Fan on it or PSU got low efficiency at idle

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by DeDeRa » Tue May 10, 2011 12:05 am

How low?

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by Abula » Wed May 11, 2011 6:36 pm

Im building a similar system, kinda intrigued by going as low as i can with the consumption, made the mistake of ordering 2x2gb of ram, but ill test it to see how much of difference it is, i ordered low voltage 1.25V Kingston Hyper Lovo, do idk how much difference it will make at the end.

But im wondering about the picoPSU, i ordred Premium picoPSU-150-XT/12.5A 150W AC-DC, out having a 24pin and 4pin cpu power connectors, so i figure was the best route, but trying to aim into a sub 20W idle setup, so im wondering if a lower brick and lower psu might not be more efficent, like Premium picoPSU-80/6.6A 80W AC-DC + 4-Pin P4 Mini Power Cable, the system should be very similar to the missingremote although im using some different components, like Intel H61 mobo and 2x2gb ddr3, 3 fans, a 2.5 5400rpm laptop hdd, so im thinking i might go a little higher than him, hoping below 20W idle, but still wondering if the 80W Pico would be a better choice than 150XT, thinking that the setup will idle at 20W and on full load maybe 60W.

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by leem » Wed May 11, 2011 9:48 pm

@Abula, I checked this with a Socket 1156 system, tried it with the 150W and the 90W, and also between a 150W power brick and a 60W power brick. There was no noticeable difference in power consumption.

I'll be checking over a few more weeks usage, but with my system I reckon I could easily get away with a 90W PSU and 80W power brick.

:)

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by Abula » Thu May 12, 2011 5:29 am

leem wrote:@Abula, I checked this with a Socket 1156 system, tried it with the 150W and the 90W, and also between a 150W power brick and a 60W power brick. There was no noticeable difference in power consumption.

I'll be checking over a few more weeks usage, but with my system I reckon I could easily get away with a 90W PSU and 80W power brick.

:)
Thank you for your reply, so by what you say, I'm going to conclude that in my case buying the 80W Picos PSU isnt worth it as it will not be more efficient than the 150XT that its already on the way to me.

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by irev210 » Tue May 31, 2011 1:00 pm

The intel mobo really does make a big difference when it comes to idle power consumption.

That's the advantage of having a motherboard that doesn't overclock - it's the most efficient. ASRock needs to support more power draw so at idle it is less efficient.

Intel motherboards + an efficient, correctly sized PSU = low power consumption

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by ces » Tue May 31, 2011 3:29 pm

irev210 wrote:That's the advantage of having a motherboard that doesn't overclock
So that is the explaination. But then why are Zotac board so far on the other side (less efficient)?

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by gakkuken » Tue Jun 07, 2011 9:21 am

wumpus and all;

inspired with this low wattage setup, i went ahead and purchased a 2100T as well but my result was way higher watts.... can someone help me sort out the problem?

i3 2100T
Gigabyte GA-H67M-D2-B3
http://www.newegg.com/Product/Product.a ... 6813128473

64GB Vertex2 SSD
2x 4GB PNY DDR3 1333
LG SATA DVD-RW
1x 92mm case fan
1x 80mm case fan
OCZ 80+ 600W power supply (only spare I have at the moment)

with this setup, my idle was around ~35 watts or so.... so it's the power supply causing the high draw?


thanks all!

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by Vicotnik » Thu Jun 09, 2011 11:32 am

Yeah, the PSU is not very efficient at such low loads. Also the Gigabyte GA-H67M-D2-B3 might be less power efficient than the Asrock board.

I don't know if it's been pointed out in this thread already, but all the Sandy Bridge processors are very power efficient at idle. PSU and motherboard determines how low you can go.

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Re: Sandy Bridge + i3-2100T -- why can't I get under 22w idl

Post by Abula » Thu Jun 09, 2011 12:22 pm

gakkuken wrote:with this setup, my idle was around ~35 watts or so.... so it's the power supply causing the high draw?
On my build im idleing 13 to 15W. Swap the Gigabyte mobo for Intel DH67CFB3 and the OCZ 600W for a Premium picoPSU-80/6.6A 80W AC-DC and your idle should go below 20W (without the optical drive), although i heard OCZ SSDs are not that efficient, specially Vertex 3. You might also need P4 extension cable (M-F) and 4-Pin P4 Mini Power Cable (for the picoPSU80).

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