Low power Sandy Bridge Mini-ITX build

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Ashex
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Low power Sandy Bridge Mini-ITX build

Post by Ashex » Sat Mar 26, 2011 5:16 pm

I desperately need to replace my desktop (which was my htpc until I sold my actual desktop) but decided to hold off until Sandy Bridge was out.

This is my tentative build for the new pc:

Asus P8H67-I

Intel i5-2500T

Zotac ECO 9800GT

WD 2.5" Scorpio 500GB

PicoPSU 160W



That's the current plan for the build. I don't plan to but the PicoPSU outright, instead I'm going to use a spare power supply I have to check the power draw of the system to decide if it will handle it. For the video card, I'm going with that one as it does not require external power (Zotac downlocked it to reduce the power requirements).


How sane is this build?

ces
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Re: Low power Sandy Bridge Mini-ITX build

Post by ces » Sat Mar 26, 2011 6:20 pm

The 2500 will have the same power usage at idle as the 2500T

Save your money and get a 2400 or 2500
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"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former" Albert Einstein

mark314
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Re: Low power Sandy Bridge Mini-ITX build

Post by mark314 » Sat Mar 26, 2011 9:56 pm

How about the Gigabyte mini-itx board, it's cheaper.

http://www.newegg.com/Product/Product.a ... -h67n-usb3

Dual HDMI, SPDIF & Coax, 2 USB3, and SATA-6. Same otherwise, except $50 cheaper.
*Disclaimer: I own a startup company in the home-theater/PC market.

quest_for_silence
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Re: Low power Sandy Bridge Mini-ITX build

Post by quest_for_silence » Sat Mar 26, 2011 11:34 pm

mark314 wrote:How about the Gigabyte mini-itx board, it's cheaper.

Usually Gigabyte BIOS is inferior to ASUS one: but 50$ may be a substantial saving.
I think it's a tough option: it may depend of how you control your fans, and of which enclosure you're going to use (give a look to their respective manuals online).
Regards,
Luca

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ces
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Re: Low power Sandy Bridge Mini-ITX build

Post by ces » Sat Mar 26, 2011 11:37 pm

quest_for_silence wrote:Usually Gigabyte BIOS is inferior to ASUS one
In what ways?
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CA_Steve
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Re: Low power Sandy Bridge Mini-ITX build

Post by CA_Steve » Sun Mar 27, 2011 11:22 am

ces wrote:
quest_for_silence wrote:Usually Gigabyte BIOS is inferior to ASUS one
In what ways?
poorer fan control, lack of UEFI comes to mind.
1080p Gaming build: i5-4670K, Mugen 4, Asrock Z97 Anniversary, MSI GTX 1660 Gaming X, 8GB 1866 RAM, Samsung 860 Evo 500GB, Crucial MX100 256GB, WD Red 2TB, Samsung DVD burner, Fractal Define R4, Antec True Quiet 140 (2 front + rear) case fans, Seasonic SSR-550FX. 35W idle, 45-55W video streaming, 170-200W WoW, 318W stress test (Prime95 + Furmark)

mark314
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Re: Low power Sandy Bridge Mini-ITX build

Post by mark314 » Sun Mar 27, 2011 5:29 pm

To each their own. I'm a fan of tried and true BIOS, personally. By the way, the Gigabyte board supports >2.2TB drives.

In 4 years, across 5 motherboards, I've never had a truly stable Asus board.
*Disclaimer: I own a startup company in the home-theater/PC market.

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Re: Low power Sandy Bridge Mini-ITX build

Post by CA_Steve » Sun Mar 27, 2011 6:07 pm

I've used both Asus and Gigabyte and think they both make decent boards....just think that Asus currently has a leg up feature-wise. Ask me again in 6 months. :D MSI is also building some nice boards.
1080p Gaming build: i5-4670K, Mugen 4, Asrock Z97 Anniversary, MSI GTX 1660 Gaming X, 8GB 1866 RAM, Samsung 860 Evo 500GB, Crucial MX100 256GB, WD Red 2TB, Samsung DVD burner, Fractal Define R4, Antec True Quiet 140 (2 front + rear) case fans, Seasonic SSR-550FX. 35W idle, 45-55W video streaming, 170-200W WoW, 318W stress test (Prime95 + Furmark)

Ashex
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Re: Low power Sandy Bridge Mini-ITX build

Post by Ashex » Tue Mar 29, 2011 10:35 am

I was looking at the 2500 but according to the intel spec page it has a 95W TDP while the 2500T has a 45W TDP.

Good call on the Gigabyte board, it has a few more options that interest me plus the power connectors are closer together which is better for the PicoPSU (I had to modify the 4-pin connector so it could reach the socket on my current desktop).

ces
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Re: Low power Sandy Bridge Mini-ITX build

Post by ces » Tue Mar 29, 2011 11:09 am

Ashex wrote:I was looking at the 2500 but according to the intel spec page it has a 95W TDP while the 2500T has a 45W TDP.
They both idle at 4 watts. That is where they will be most of the time. They are so muscular that even when in use neither will push much more than 10 watts.

They are the same except the 2500T is artificially limited at the high end. You will seldom go there. If you do it will be because you choose to do so. Why forgo that option.

Why pay more for a governor on you engine?
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Falkon
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Re: Low power Sandy Bridge Mini-ITX build

Post by Falkon » Tue Mar 29, 2011 11:25 am

ces wrote:
Ashex wrote:I was looking at the 2500 but according to the intel spec page it has a 95W TDP while the 2500T has a 45W TDP.
They both idle at 4 watts. That is where they will be most of the time. They are so muscular that even when in use neither will push much more than 10 watts.

They are the same except the 2500T is artificially limited at the high end. You will seldom go there. If you do it will be because you choose to do so. Why forgo that option.

Why pay more for a governor on you engine?
Those are very good, valid points, but if the OP is limited by a 160w PSU it may be prudent to have the CPU artificially limited from exceeding a certain consumption.

ntavlas
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Re: Low power Sandy Bridge Mini-ITX build

Post by ntavlas » Tue Mar 29, 2011 11:30 am

I agree with ces, besides it should be fairly easy to turn the regular 2500 into a 45 watt cpu by lowering the voltage to 2500t`s levels (and lowering clock speed if you have to). While intel doesn`t guarantee that the 2500 will reach 2500t`s speeds at the same voltage, you should get pretty close. Not worth paying the price premium imo, especially when the cpu will be idle most of the time.

ces
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Re: Low power Sandy Bridge Mini-ITX build

Post by ces » Tue Mar 29, 2011 11:40 am

Falkon wrote:if the OP is limited by a 160w PSU it may be prudent to have the CPU artificially limited from exceeding a certain consumption
That is a good point.

Those T chips are so needless expensive though. Don't they have some 67 watt Sandy Bridges that aren't so expensive?

I just went and looked it up. The i5-2400S is 65 watts. Newegg sells it for $202.99.

I just noticed the OP is putting a video card on it. I guess he needs every spare watt he can find.

What do you think?
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djkest
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Re: Low power Sandy Bridge Mini-ITX build

Post by djkest » Tue Mar 29, 2011 1:03 pm

I'd be interested to see how the project goes, although the i3-2100 seems like a better choice for a "very low power" system.

I'm wondering, with enough underclocking, how low you can get the voltage? It would still spank something like an Atom, even at a measley 2.0GHz with turbo boost disabled.

Mats
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Re: Low power Sandy Bridge Mini-ITX build

Post by Mats » Tue Mar 29, 2011 1:40 pm

You haven't told us what you're going to use it for, or what case you're going to use, or what computer you're using right now.

Are you absolutely sure that 4x2.3 GHz (i5 2500T) is better than say 2x3.1 GHz (i3 2100, half the price)?
The i3 2100 + cheap SSD + HDD will most likely be faster than a 4 core + HDD in many scenarios.

Also, that graphics card is not the most logical choice, but then again, you haven't told us what you're going to use it for..
It's old, underclocked but still have a fan, and if you choose to swap heatsink you loose the warranty.
Are you sure that the integrated graphics isn't enough?

For the millionth time, :D TDP is a limit. You should read it as <95 W. All 1155 CPU's use less than ~70 W under full CPU load.

The overpriced 2400S uses 10 W less than the faster 2300 during CPU burn, it's not a 30 W difference (TDP difference).
http://www.xbitlabs.com/articles/cpu/pr ... 2400s.html

Now we're talking about the 2500T. If we take the power consumption for the 2300 from the link above, 50.7 W,
and adjust the clock speed from 2.8 (i5 2300) to 2.3 GHz (i5 2500T) with this (or a calculator), you get 41.6 W, which is under 45 W.
That's even without touching the Vcore.

I see no reason to buy the 2500T, the 2300 is a much better choice. If anyone else chooses to burn their money... well, it's their money. :lol:

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Re: Low power Sandy Bridge Mini-ITX build

Post by ntavlas » Wed Mar 30, 2011 3:07 pm

Video encoding would make good use of the quad core otherwise I agree that a dual core would be a better choice with it`s faster clock and lower power consumtion. I don`t think it`s necessary to use a T series cpu in order to keep power use in check. Simply reduce the voltage until you reach the desired power level, then see how high you can clock it at this voltage. Even if you end up at ~2-2.4 ghz the i3/i5 cpu will still beat any atom or zacate and should be enough to drive a 5670 video card without being a bottleneck.

ces
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Re: Low power Sandy Bridge Mini-ITX build

Post by ces » Wed Mar 30, 2011 3:40 pm

Mats wrote: Are you absolutely sure that 4x2.3 GHz (i5 2500T) is better than say 2x3.1 GHz (i3 2100, half the price)?
You can't be too rich, too thin or have too many GHz :D
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Re: Low power Sandy Bridge Mini-ITX build

Post by CA_Steve » Wed Mar 30, 2011 6:44 pm

ces wrote:You can't be too rich, too thin or have too many GHz :D
...Unless you are an ascetic lottery winner that builds a hut perched on a wireless basestation tower.
1080p Gaming build: i5-4670K, Mugen 4, Asrock Z97 Anniversary, MSI GTX 1660 Gaming X, 8GB 1866 RAM, Samsung 860 Evo 500GB, Crucial MX100 256GB, WD Red 2TB, Samsung DVD burner, Fractal Define R4, Antec True Quiet 140 (2 front + rear) case fans, Seasonic SSR-550FX. 35W idle, 45-55W video streaming, 170-200W WoW, 318W stress test (Prime95 + Furmark)

Ashex
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Re: Low power Sandy Bridge Mini-ITX build

Post by Ashex » Sat Apr 02, 2011 6:27 pm

I really should log in more often :oops:

Right now I'm running the following:


Zotac GF9300-D-E (Rev 0) mini-itx board
2GB DDR2-800 (Tried upgrading it to a 4GB kit but pc fails to post, too cheap to buy another kit)
Intel E7200 proc
WD 2.5" Scorpio 500GB
PicoPSU 90W


This was originally built to be a HTPC and worked great as one, but I'm using it for a desktop and it doesn't work so great (I'm exporting a set of shots right now and the computer is crawling).

I primarily do photo/video editing with Lightroom and Premiere, I'm under the assumption that both these apps will take advantage of all cores on a quad-core.

I do some gaming which consisted of StarCraft 2 and eventually Diablo 3 (whenever that comes out) so I just want a card that can handle gaming fairly well. I am shooting to cram the entire build through a PicoPSU so I went with that card since it can run off the PCIe power.

Regarding the case, I'm going to see how my current file server case works, which is a APEX MI-100. I'm going to replace it with the Lian Li PC-Q08 as I'm going to rebuild the file server using the hardware off the htpc and add more drives to it.


I have never been an expert at underclocking so for the most part I've avoided it especially since a seemingly stable clock under regular usage will crash the OS when I'm rendering.

ces
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Re: Low power Sandy Bridge Mini-ITX build

Post by ces » Sat Apr 02, 2011 8:34 pm

Ashex wrote:Zotac GF9300-D-E (Rev 0) mini-itx board
2GB DDR2-800 (Tried upgrading it to a 4GB kit but pc fails to post, too cheap to buy another kit)
What memory are you using. I bought that board on sale a while back. I was planning on loading it up with 8G of the approved memory (2 sticks of Kingston KVR800D2N6/4G).

Think I will have a problem?
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"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

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Re: Low power Sandy Bridge Mini-ITX build

Post by CA_Steve » Sat Apr 02, 2011 9:19 pm

Just so you know, old video cards have crappy idle power. The stock 9800GT uses ~35W. I can't imagine the Zotac will use much less. A current gen card will idle at 10-15W. So, any efficiencies you might hope to get by using the picopower PSU and a gaming video card without an external connector just went out the window. We don't know what resolution you want for gaming, so can't recommend a specific gpu.

Yes, quad core = good for Lightroom and Premiere. Faster is also good. So, getting some downclocked/lower TDP variant is just slowing down your apps and costing you $'s. All of these Sandy Bridge quad cores will idle at about the same power level regardless of their rated speed/TDP. Consider the i5-2500k.

Don't know how much money you want to throw at this, but the HDD will probably be your bottleneck. Consider an SSD for boot/apps.

Here's a recent review at Hexus using an i5-2500k, Intel P67 mobo, SSD, Corsair AX750, and a variety of video cards (not recommending the one reviewed - it's just a nice look with modern platform and includes a Starcraft benchmark). Idle AC power is 42-50W, gaming load is 96-160W with midrange to upper midrange video cards.
1080p Gaming build: i5-4670K, Mugen 4, Asrock Z97 Anniversary, MSI GTX 1660 Gaming X, 8GB 1866 RAM, Samsung 860 Evo 500GB, Crucial MX100 256GB, WD Red 2TB, Samsung DVD burner, Fractal Define R4, Antec True Quiet 140 (2 front + rear) case fans, Seasonic SSR-550FX. 35W idle, 45-55W video streaming, 170-200W WoW, 318W stress test (Prime95 + Furmark)

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Re: Low power Sandy Bridge Mini-ITX build

Post by tim851 » Sun Apr 03, 2011 6:24 am

ces wrote:They are so muscular that even when in use neither will push much more than 10 watts.
What?

Is there a reference for that?

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Re: Low power Sandy Bridge Mini-ITX build

Post by ces » Sun Apr 03, 2011 6:47 am

tim851 wrote:
ces wrote:They are so muscular that even when in use neither will push much more than 10 watts.
What? Is there a reference for that?
I should have qualified that as a guess based on reviews of other members of the Sandy Bridge family (such as on SPCR). What kind of wattage do you think it will use?
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"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

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Re: Low power Sandy Bridge Mini-ITX build

Post by tim851 » Sun Apr 03, 2011 11:07 am

ces wrote:I should have qualified that as a guess based on reviews of other members of the Sandy Bridge family (such as on SPCR). What kind of wattage do you think it will use?
First off, a 2400S uses around 25w less under load than a 2300, according to this page. If it uses 25w more, it can be concluded that the power usage of a Core i5-2300 exceeds 10w. The 2400S is rated at 65w, the 2500T is rated at 45w, so I'd venture a guess that Intel has dialed down load voltage even more, so the load power usage difference between a 2500 and a 2500T is probably north of 30w.
It can be argued that the CPU will spend more time idle. This is not necessarily true. You don't know what people do with their machines. Some have it search for E.T. or decode our DNA instead of idling.
And even if it idles for 99% of it's lifetime, in the 1% of time it spends under load, it still needs to be sufficiently cooled. A 2500T can inarguably be cooled more easily/efficient/quiet than a regular 2500. If this is worth the price premium and the lack of raw power (due to lower clock speed) is then debatable.

Secondly, and this is what raised my eyebrows, you insinuated that the Sandy Bridge CPUs were so powerful that they never would be stressed properly. This seems to follow an analogy like "a 250 pound linebacker might lift a keg of beer with one arm, while a 130 pound golfer will pull his back trying".
And this is overly simplified. Yes, there are plenty of scenarios where a Pentium II class processor would compute for 5 minutes while a Sandy Bridge will only snap up to 100% for a split second before returning to idle. But a person buying a modern quad-core usually intends to use if for something. Every application that can stress all four cores of a Sandy Bridge processor will make it dissipate its max power. And you won't need futuristic or exotic applications for that.
The brute force of the Sandy Bridge will only reduce the time it's on load, not the power it dissipates while there.

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Re: Low power Sandy Bridge Mini-ITX build

Post by quest_for_silence » Sun Apr 03, 2011 1:12 pm

tim851 wrote:
ces wrote:I should have qualified that as a guess based on reviews of other members of the Sandy Bridge family (such as on SPCR). What kind of wattage do you think it will use?
First off, a 2400S uses around 25w less under load than a 2300, according to this page. If it uses 25w more, it can be concluded that the power usage of a Core i5-2300 exceeds 10w. The 2400S is rated at 65w, the 2500T is rated at 45w, so I'd venture a guess that Intel has dialed down load voltage even more, so the load power usage difference between a 2500 and a 2500T is probably north of 30w.

Just a side note.

While I'm a fan of HT4U, there are also to consider two facts.
First of all, historically "S" Core processor didn't give substantial power consumption advantage over relevant standard-clocked processors.
Secondly, Xbit Labs have noticeably different findings, as you may already know.
Regards,
Luca

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Re: Low power Sandy Bridge Mini-ITX build

Post by ces » Sun Apr 03, 2011 1:33 pm

tim851 wrote:First off, a 2400S uses around 25w less under load than a 2300, according to this page. If it uses 25w more, it can be concluded that the power usage of a Core i5-2300 exceeds 10w. The 2400S is rated at 65w, the 2500T is rated at 45w,
My understanding (gained from this forum, SPCR, Xbits and Anand) is that the lesser Sandy Bridge chips are just hobbled 2500 chips with governors that enage only when they start reaching higher loads. They all idle at the same speed. The hobbled chips are blocked from higher speeds. They are like engines with governors on.

Basically it is the amount of work that generates the heat, not the chip (at least within the same chip design). While everyone's usage is different, unless you are doing encoding or other heavy work, you aren't going to stress any of these chips and they will all be running far under the TDP.

Here are some energy usage numbers comparing the 2 core 2100 with the 4 core 2400
http://www.silentpcreview.com/article1179-page5.html
http://www.silentpcreview.com/article1179-page3.html
in my opinion surprisingly similar... as long as you aren't talking about full load.

This one shows the difference between idle, normal usage and full load.
http://www.silentpcreview.com/article1148-page5.html
Here there is not much more than a few watts of difference with the 2500K running at idle compared to it running at a normal load.

Right now I am doing a bit of Multi-tasking and my little 2 core clarkdale is running at 3-8%. It is running a little under 30C. Many people here run weak last last generation dual core cpus and never put that much of a strain on them.

I would expect the Sandybridge to run even cooler with the same load. If you study the data on the above links I believe you would find it difficult to come to any other intellectually honest conclusion. I think what is really amazing is it appears that at idle the power draw of the 2500K is approximately 4 watts and this rises only a few watts at moderate usage. So what if you cut that in half???? The efficiency of the motherboard is a greater factor than the efficiency of the CPU! Talking about relative efficiency of CPUs is so last generation. :)

But I have observed you to be a fairly knowledgeable fellow. I think you know all that. So what is the gotcha? Maybe I inadvertently misstated something? No problem. If so I will correct it. But the facts are the facts. Everyone gets their own opinion but not their own facts.

So tell me, what am I missing? Or what were you missing?
Last edited by ces on Sun Apr 03, 2011 4:00 pm, edited 6 times in total.
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"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

ces
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Re: Low power Sandy Bridge Mini-ITX build

Post by ces » Sun Apr 03, 2011 1:56 pm

xbitlabs.com wrote: However, if you decide to go with Core i5-2400S or any other similar processor from the S-series, you should keep in mind a few things. Most importantly, Intel doesn’t preselect better semiconductor dies for their energy-efficient models, but simply lowers the clock speeds, as simple as that.
xbitlabs.com wrote:Frankly speaking, Core i5-2400S not only performs worse than Core i5-2400, but also can’t boast the best performance-per-watt ratio, which is pretty strange for an energy-efficient model. On the other hand, even regular Sandy Bridge processors do not consume that much power to begin with and may suit perfectly fine for small and quiet systems.
http://www.xbitlabs.com/articles/cpu/di ... 00s_7.html
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"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

tim851
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Re: Low power Sandy Bridge Mini-ITX build

Post by tim851 » Sun Apr 03, 2011 3:53 pm

ces wrote:in my opinion surprisingly similar... as long as you aren't talking about full load.
I am talking about full load.
The OP thinks about getting a PicoPSU. In a system with a quad-core processor AND a dedicated graphics card that can handle StarCraft II. He probably chose a 2500T to limit peak load.

Even if a CPU spends the majority of its lifetime idling or watching videos at 12% load, the power supply and the cooling system must be laid out for the not too unlikely event that it will run at full load. With the OP also clearly stating that he will make use of Lightroom and Premiere, there will probably be some good amount of full load time, wouldn't you say?

And once again: full load of a 2500T is lower than of a 2500. How much seems arguable. Websites sadly seem to have a hard time coming up with comparable results. It should also be noted, that full load on a CPU, simulated by Prime95 for example, is not the same as full load on a GPU, as simulated by Furmark which puts an "unrealistic" strain on the card.
This one shows the difference between idle, normal usage and full load.
http://www.silentpcreview.com/article1148-page5.html
Yes. And it shows that fully stressed a Core i5 2500K increases system load by ~70w. That's probably in excess of 60w just CPU power consumption. The Core i5 2400S was shown to use less, 25w by ht4u, 10w by xbitlabs. If we meet in the middle it's about 17w. The Core i5 2500T is rated at even less power draw.

Also, it doesn't say "normal usage", it say H264/MKV playback.
You have repeatedly made the error and concluded from yourself on others, but can't just presume that watching a movie is more normal than playing a video game or video encoding. With the OP explicitely stating he'll be doing video/image editing, for him, these are normal usage.
Right now I am doing a bit of Multi-tasking and my little 2 core clarkdale is running at 3-8%. It is running a little under 30C.
Good for you, but are you saying that nobody needs quad-core Sandy Bridges?

ces
Posts: 3395
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Location: US

Re: Low power Sandy Bridge Mini-ITX build

Post by ces » Sun Apr 03, 2011 5:08 pm

ces wrote:But I have observed you to be a fairly knowledgeable fellow. I think you know all that. So what is the gotcha?
tim851 wrote:I am talking about full load.
I was not. I failed to make that sufficiently clear. (it's hard to defend against intentional "gotcha" misinterpretation, See: viewtopic.php?p=537813#p537813 ).

So I am making it clear now. I can't make it any more clear than this: When I said that, I was not talking about encoding or gaming. So what. What is all the indignation about? :)

When you talk about full load, you are talking about benchmarking programs, which I understand are designed to generate an artificially heavier load than you would can ever expect from typical encoding or gaming. I most definitely was not talking about that.

Can any gamer out there say what percentage of a load Starcraft or Diablo can be expected to impose on a Sandy Bridge? What about encoding, can that be expected to saturate a Sandy Bridge like a benchmarking program? If the load is 25%, with a little research I might consider standing behind my original "10 watts" statement even then.
Ashex wrote:How sane is this build?
After I made my comment, Ashex indicated he does mostly photo/video editing, and plays StarCraft 2 and eventually Diablo 3 and is thinking about a Lian Li PC-Q08. Hard to tell whether the video editing he does is of a type that would put a heavy load on the CPU for lengthy periods of time.

What is right for Ashex, he will determine.

But it seems like a smaller Seasonic PSU in a PC-Q08 with a 2400 would be a reasonable proposal to make for his consideration. It will not burn up many more watts per month and will handle whatever encoding he does more quickly and crisply... and will permit him to add storage to the Q08 to store images etc in the future should he ever want to. And a 160 watt Pico PSU isn't that cheap. I don't think this will cost that much more. I think you can get a good Seasonic PSU for about $120 bucks. How much does the 160 watt Pico PSU cost?

Any gaming he does I expect was always going to be limited by the video card, not by which version of Sandy Bridge he chose.

Do you disagree?
tim851 wrote:Good for you, but are you saying that nobody needs quad-core Sandy Bridges?
As I have said before: You can't be too rich, too thin or have too many GHz (or cores)
ESPECIALLY if they don't cost much in the way of dollars or watts.... Why not? :D
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"Aristotle calls man the rational animal. All my life I have been seeking evidence to confirm this" Bertrand Russell
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quest_for_silence
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Re: Low power Sandy Bridge Mini-ITX build

Post by quest_for_silence » Mon Apr 04, 2011 2:19 am

ces wrote:What about encoding, can that be expected to saturate a Sandy Bridge like a benchmarking program? If the load is 25%, with a little research I might consider standing behind my original "10 watts" statement even then.

I think that it may be still a too much low guesswork, which could need further assessments.

Just for example, actually (on a 2500K running @ stock) rendering a 1024x768 image with 2xAA enabled leads to a 46-47W average CPU power for 39secs: it's apparently not too far from the around 65-66W level estimated by SPCR while running Prime95 (for the 12V: does the Sandy Bridge draw some power from 3.3V/5V rails, as previous "Core i" CPUs do?), and besides it's noticeably more than the above alleged 10W level.

Not to mention the possibility of recurring that (historical) hot spot issue seen on the Nehalem architecture (which I don't know if it's applicable even to Sandy Bridge).
Regards,
Luca

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