Building a quiet system- Should I use a mobile cpu?

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Wabbit
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Building a quiet system- Should I use a mobile cpu?

Post by Wabbit » Mon Jan 28, 2008 8:53 am

I have an older desktop pc that I use for low resource stuff. Mainly, it is the wife and kids' pc for web browsing, making greeting cards, etc. It has an older processor and is somewhat loud. I would like to quiet it down and also turn it into a network file server (have 2 or 3 drives, separate from the system drive, in Raid 1 or 5). I plan on using a lower-end Core 2 Duo. I plan on keeping the case, which is an old CoolerMaster, but I can replace everything else.

So I would like some suggestions for parts, and also, should I consider one of the mobile Intel processors? As I understand it, they are designed to run cooler by stepping down when the processing power is not needed.

Thanks for any help!

aaa
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Post by aaa » Mon Jan 28, 2008 9:01 am

The desktop Core 2's also step down when power is not needed.

Basically there is less of a need for mobile processors because of the above.

Did you also consider AMD processors? They also step down, and there is a cheaper motherboard selection.

AuraAllan
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Post by AuraAllan » Mon Jan 28, 2008 9:05 am

Hi Wabbit, welcome to SPCR !

AMD's LE-1100 is worth taking a look at. It runs very cool and should provide more then enough power for your needs.

autoboy
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Post by autoboy » Mon Jan 28, 2008 10:44 am

MoDT (mobile on Desktop) was popular around here during the Pentium D and 85W AthlonX2 era. It has pretty much gone away IMO since the new desktop processors use very little power. I would consider either a cheap AMD system (they have the same stepdown as their mobile counterparts) or an Intel system with a Pentium Dual core. I wouldn't even look at the Core 2s. They are all the same chip anyways. The Pentiums just have less cache. The new Celeron dual core chips have even less cache, 512KB, and it makes them considerably slower than AMD chips which are less dependent on cache size.

Most of the low spec Intel chips don't step down in speed like the more expensive Core 2s while at idle. Overall, AMD, since they all step down to 1Ghz (except some of the Sempron models) have lower idle power consumption than Intel chips, while the Intel chips use less power at load. Make sure you set your power saving settings to mobile/laptop or the processor will never step down.

An AMD 4100+ and AMD 690 board are your best bets for low power consumption, quiet operation, inexpensive, and good performance. As for building a quiet PC, there is much more than just picking the right processor and board. The power supply, harddrives, case, fans, and fan control are more important now that the Pentium 4 is gone.

Wabbit
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Thanks!

Post by Wabbit » Mon Jan 28, 2008 11:33 am

Wow, thanks for the quick and very kind responses! Sometimes you post to a question to some boards and have to wade through a flame war to get good information.

I haven't looked at AMD's for several years since my the last P I built was a gamer and so I went with a Core 2 Duo. Also, the last time I built an AMD system, it was a good processor, but had issues with heat. But I think you have a good point that for my needs, AMD might be the way to go, and I imagine they must have resolved their heat issues by this point.

AuraAllan, I looked at the LE-1100's on Newegg and it looks like they are AMD's version of the Celeron. I don't think I want to go that low, performance wise. The kids will probably play some basic games and such. I hope to run a passively cooled video card and perhaps the only fan, other than the heat sink fan would be a super quiet 120mm fan for the 3 disk array I plan to use for the network storage.

Autoboy, I looked for the 4100+ on Newegg, but they didn't seem to have any. I imagine I could go a step up to 4200+ with as good a result? What socket option should I be looking for with AMD?

Thanks for the help!

AuraAllan
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Re: Thanks!

Post by AuraAllan » Mon Jan 28, 2008 11:48 am

Wabbit wrote:AuraAllan, I looked at the LE-1100's on Newegg and it looks like they are AMD's version of the Celeron. I don't think I want to go that low, performance wise. The kids will probably play some basic games and such. I hope to run a passively cooled video card and perhaps the only fan, other
My girlfriends computer runs a LE-1100 on a ASUS M2A-VM HDMI board using onboard GFX and it runs "Sims 2" and "My horse and me just fine".

Wabbit
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Re: Thanks!

Post by Wabbit » Mon Jan 28, 2008 11:55 am

AuraAllan wrote:My girlfriends computer runs a LE-1100 on a ASUS M2A-VM HDMI board using onboard GFX and it runs "Sims 2" and "My horse and me just fine".
Hmmm... So I guess if I went with that cpu, it would be easier to passively cool than a 4200+? Don't the Sempron/Celeron lines cut out some processor features?

AuraAllan
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Re: Thanks!

Post by AuraAllan » Mon Jan 28, 2008 11:59 am

Wabbit wrote:Hmmm... So I guess if I went with that cpu, it would be easier to passively cool than a 4200+? Don't the Sempron/Celeron lines cut out some processor features?
The LE-1100 is a single core CPU while the 4200+ is a dual core.
Im pretty sure the 4200+ runs cool aswell but the LE-1100 should be easier to cool passively.

AFAIK the Semprons has the same features a all other (mainstream) AMD cpus.

Edit: The 4200+ cost 2.5 times more then the LE-1100 here. Dont know about your local prices.

autoboy
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Post by autoboy » Mon Jan 28, 2008 12:23 pm

Oops. I mean the 4000+. It is $53 on Newegg. Not sure how much it is there? Get whichever chip you feel gives you more performance for your $, but stick to the 65nm chips. As for heat? it is not a problem with these chips. They are 65W processors, but they probably use more like 40W at full load and only a few watts at idle. You can always use a program calle CrystalCPUID to lower the voltages on the CPU if you want to get more extreme. Lowering voltage has a dramitic effect on heat. You can't lower the voltage in software on many of the Intel chips, which is another reason I prefer AMD. I just got an Intel notebook and I am really dissapointed to find that I can't adjust the voltage. I didn't do my homework on that one. I knew I should have gotten the AMD version. The fan turns on every 10 min or so. It is quiet, not not silent and the fact that I can't do anything about it kills me.

As for elaborate passive cooling, it is not required. Get yourself a Arctic Cooling Alpine7 or Freezer7 and set the fan control. Those things are pretty much inaudible. For your first silent PC, you will be surprised to find that all it takes is selecting the right quiet components. Fanless is harder, more expensive, and not required to get quiet.

Bugsi
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Post by Bugsi » Mon Jan 28, 2008 10:21 pm

Consider the AMD BE2300 and BE2350 processors. Low power but still full dual cores.

Wabbit
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Post by Wabbit » Thu Jan 31, 2008 4:29 am

So if cost of the processor was not the issue, but decent performance was secondary only to the ability to run cool and quiet, what would be the best choice?

I couldn't find anything about BE type processors on Newegg...

jaganath
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Post by jaganath » Thu Jan 31, 2008 5:47 am


Wabbit
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Post by Wabbit » Thu Jan 31, 2008 6:16 am

Huh, don't know how I missed that... So now I am basically trying to decide between the AMD Athlon 64 X2 4000+ Brisbane 2.1GHz 65W Dual-Core and the AMD Athlon X2 BE-2350 Brisbane 2.1GHz 45W Dual-Core.

Will a 20W drop account for a lot of heat difference, enough to be worth spending $25 more? Is there a big performance difference? I won't be playing any major games on this pc, but will probably use it as a media center from time to time.

Also, how does the retail heatsink stand up for cooling/quietness? I was considering buying one of those big Ninja heatsinks, or a Thermaltake. Looking at some of the Newegg reviews, some people say you could run the 45W CPU on just a heatsink! Is that realistic?

Thanks!

Bugsi
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Post by Bugsi » Thu Jan 31, 2008 6:07 pm

The retail heatsink will cool the CPU without problems, but it will be noisy because it uses a smaller, faster-spinning fan. To reduce the noise, you need to either do away with the fan or slow the fan a lot more, with the tradeoff being that you'll need a heatsink with a larger surface area. I think it is realistic for a Ninja to cool a CPU alone if there is otherwise good airflow through the case with large case fans. Alternatively, one can use the 120mm Scythe fan that comes with the Ninja to get more airflow over it. I did that in one build and it works very nicely. You can spin larger fans slower over a large heatsink, and dramatically reduce or eliminate the CPU cooler as a noise source.

autoboy
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Post by autoboy » Thu Jan 31, 2008 10:50 pm

I highly recommend the Arctic Cooling Alpine 7 heatsink for low power HTPC builds. It is low profile, very cheap, and effective at low RPM. It cannot handle overclocked processors, but I use them in most of my rigs with great success. If you are looking at alternatives to the AC7, make sure that you take the height of your case into consideration. The Scythe Mini Ninja is recognized as the best HTPC heatsink around here, but for these lower power builds, I find that the AC7 is sufficient for keeping the CPU cool enough, is considerably cheaper, and is inaudible in a case. Highly recommended.

The 45W processors are generally pulled from a better bin than the 65W processor to run at a lower voltage than the 1.35V 65W processor. However, since 2.1ghz is a pretty low clock, you can use a software program like CrystalCPUID or RMClock to undervolt the processor even lower than the 1.25V that the 45W processors run. Many find that the 2.1ghz chips can undervolt to around 1.1V. Undervolting is like overclocking in reverse. Instead of running up the clockspeed, you reduce the voltage and run stability programs to make sure that you are stable. At 1.1V it would be more like a 30-35W processor than 65 or even 45W. So, if you don't want to undervolt and just want a nice 45W processor, the BE is a nice choice. If you are comfortable with finding your processor's undervoltling limits, then you can buy the 65W version.

I have to correct myself about the intel chips. It looks like most Intel chips now support Enhanced speedstep that allows you to undervolt just like the AMD chips. Still, I maintain my recommendation that AMD platforms still rule the budget realm.

Wabbit
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Post by Wabbit » Fri Feb 01, 2008 4:55 am

Thanks for the great information! I think I will go with the 45W BE-2350, and either the AC7 or Scythe Mini Ninja. Thanks for the great advice!

Now on to my next question...

Bugsi
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Post by Bugsi » Fri Feb 01, 2008 3:47 pm

I also would say to consider a Thermalright XP-120 for HTPC builds, as well as the Zalman CNPS8700LED for low-profile builds. I use both with good results.

And a brief note, undervolting isn't quite like the opposite of overclocking. Saying that it is, implies that undervolting makes your CPU run at a slower clock speed. This is not the case. Let's clarify:

Normal operation = Normal clock speed, Normal voltage.
Overclocking = Faster clock speed, normal voltage.
Undervolting = Normal clock speed, lower voltage.

(Please correct me if overclocking ever requires overvolting, I don't overclock, so I don't know.)

Undervolting is simply making use of the lower-than-spec range of voltages that your CPU will continue to run without instability or lockup. If your CPU will run reliably at lower voltage, you get the same clock speed but get it with less power.

Again, people are welcome to correct me on that if I have it all wrong. Thus, undervolting is a seriously simple way to lower your temperatures, provided your CPU continues to run normally.

autoboy
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Post by autoboy » Sat Feb 02, 2008 10:02 am

When I say that undervolting is like overclocking, I am indicating that it can cause instability and you need to run the same stability programs as if you were overclocking. Underclocking is the opposite of overclocking. I was assuming they could tell the difference between voltage and clock.

Bugsi
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Post by Bugsi » Sun Feb 03, 2008 12:14 pm

autoboy wrote:When I say that undervolting is like overclocking, I am indicating that it can cause instability and you need to run the same stability programs as if you were overclocking. Underclocking is the opposite of overclocking. I was assuming they could tell the difference between voltage and clock.
That's an excellent clarification. Yes, stability is the key factor to watch for in both cases to find the limits that your CPU will undervolt or overclock.

On the subject of the difference between the two, I've actually run into many people who don't understand exactly what undervolting does, where they say they don't want to undervolt because they don't want their system to run slower. Even after explaining that a stable-running undervolted system runs at the exact same speed as without undervolting, they look at me like I'm insane and say something like "Well no, if you run at a lower voltage, your computer will run slower." -When I read your statement about underclocking being the opposite of overvolting, I read it as a literal statement, and just wanted to clarify, since I've run into confusion about the issue.

Undervolting, if your system will run stable, simply uses less electricity, and thus produces less waste heat. The analogy I use to explain it to people is that it's like tuning your car's engine to get better gas mileage. You go the same speed, you go the same distance, but it uses less fuel.

autoboy
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Post by autoboy » Mon Feb 04, 2008 2:41 pm

Let's let MikeC and Jan explain it. Linky

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