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Socket 775 PD 2.8 820 Heat Question

Posted on 2006-05-19
Medium Priority
Last Modified: 2008-02-01
I am building a Digital Audio Workstation (DAW) that will be used at a live semi-outdoors event.  I am wondering what the thermal limits of stable and safe operation are for a computer.  The ambient temperature at the event could climb to 40C, the temperature in the rack will climb beyond this.  The system is mounted in a 4u server style rack case.  I need to know if this system will have thermal problems, because I am supposed to make a multi-track recording of a live event with this setup.  Is there anything that I should be aware of?  My chip is already running at 50-55C at room temp ~23C.  The hard drives are mounted directly above each other without much airflow.  The case has a fan at the front, and the P/S is drawing it out, but I don't know if that will do enough, and I really would rather not deal with the hassle of water-cooling.  Please advise.

Computer consists of the following:

Intel D945GNT Mobo
PD 2.8  820
Hyper 48 Heatsink (stock paste)
2x Seagate 200GB SATA II (Raid 0)
1 Maxtor 250GB PATA HD
1 WD 40GB PATA HD (OS Boot disk)
1 Plextor DVD-R
1 Sony DVD-R
1 IDE controller card
550w Ultra X-connect P/S
2GB DDR2 Ram (OZZY or some such brand)
1 RME Digi9652 Sound Card
1 PNY Nvidea GeForce Dual VGA 128mb PCI graphics card (5500 i think)

Question by:sound2man
  • 7
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Expert Comment

ID: 16722928
First I would recommend a faster CPU.

IF you would like to be on the ball :

Chose a bigger case.
Have 3-4 case fans. ( 2 in 2 out )
You may consider getting HD fans.
Wiring is very important. Clean wiring will allow air flow smoothly in the system which would drop the temps. Hide your wires well.

Author Comment

ID: 16722945
1.  I actually just got this CPU, and think it will be overkill for my application.  I really don't need more speed, or more heat from a more powerful CPU.  

2.  I can't get a bigger case.  I don't have anymore room in my rack, and cases bigger than 4u are not generally used in portable, live recording.  For that matter, most people go smaller.

3. Don't have room for HD fans.  These drives are piggybacked because there isn't room for anything else.

4. With the amount of stuff in this computer, it is hard to keep wireing hid, although I did the best I could.  This is what influenced me to get the X-connect PSU.  This way I only have the necessary wires in the case.
LVL 70

Expert Comment

by:Gary Case
ID: 16723406
Well ... this is a real challenge.  The thermal spec for a P4D-820 is 64.1 °C => and you're already running at 55 with a 23 °C ambient !!   This does not bode well for an environment where the temp hits 40 °C.    The LAST thing you want is a "... faster CPU." !!   Your 820 is already dissipating 95 watts -- the 830 & 840's generate 130 watts !!  (although they do have higher thermal specs -- 69.8)

A 4U case SHOULD have room to mount a Zalman 9500 heatsink/fan combo -- this is far and away the best air-cooled solution I'm aware of.   The thermal resistance of this unit is only 0.12 °C/W, which means your 95 watt CPU (an 820) will only raise the temperature by 11.4 °C.   That's VERY good performance for a heatsink -- my Zalman 7000 (also a very good heatsink) has nearly double the thermal resistance !!
Here's a link to purchase:  http://www.newegg.com/Product/Product.asp?Item=N82E16835118003
... and here's the detailed measurements, if you want to confirm you have space for it (a good idea):  http://www.zalman.co.kr/product/cooler/9500_LED_775_eng.html

If you replace your current heatsink with a 9500; and use Artic Silver 5 thermal compound (much better than what's generally shipped with heatsinks) you should notice a significant reduction in your idle temps.   Be sure to completely clean the old compound off the CPU before applying the Artic Silver -- and follow the instructions on Artic Silver's page:  http://www.articsilver.com/arctic_silver_instructions.htm (note paragraph 9 for your CPU)

That modification should make a nice difference.   Other than that, I'd suggest you insure you have as good an airflow arrangement as possible;  and try to keep the rack in a shaded location so the problem is not further aggravated by direct sunlight.  

One good thing is that Intel CPU's don't simply shut down at the thermal spec temp -- they will actually continue to work quite well until about 80 °C, at which point they begin a thermal shutdown process.   It's a BAD idea to ever run above 70 °C, however, and you SHOULD never run above the thermal spec -- although in the situation you've described that may be difficult when ambient gets that high.

I'd put the best possible cooling you can on the CPU (a 9500 unless it simply won't fit -- but based on the height of a 4U case and the height of the 9500 I'm fairly sure it will), make any improvements you can to the case airflow, and be sure you keep the inside of the case fairly dust free (blow it out with compressed air frequently).   With those precautions, I'm sure the system will run just fine.
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Author Comment

ID: 16725046
I was hoping that I could make do with my current heatsink.  A 9500 would be nice, but
a)it's not in stock anywhere in my area and I don't have the time to wait for it  
b)it is quite noisy
c) I already have the hyper 48.

I did check if it would fit, and it looks like it would.  However I would rather not go there at this time.  I did order a tube of Arctic silver, and will be applying it when it arrives if I have any problems.  What I am really concerned about is the fact that the fan on the hyper 48 never kicks into high speed, regardless of how hot the CPU is.  it is always sitting at a nice slow 1,580.  The speed is supposedly controlled by the mobo, but why won't it kick into high gear.  I can't get adequate cooling with this low speed.  It is supposed to reach speeds of 3,200 rpm, but it won't kick up to there, nor does the rpm change when I try to up it in speedfan.  Have any idea why?  I noticed in device manager there is an unworking device called SMbus that I don't seem to be able to find drivers for, does this have anything to do with it?
LVL 70

Expert Comment

by:Gary Case
ID: 16725529
"... it is quite noisy ..." ==> What !!   It's one of the quietest units you can buy !!  At the lower fan setting it's virtually silent; and even at the highest setting it's barely audible.    If you don't want to replace heatsinks, fine -- but noise level is NOT a consideration with this unit.    Newegg, by the way, will ship overnight (for ~ $20 extra).   Your choice -- but since you're going to take out the other unit and clean off all of the old thermal compound anyway (to apply Artic Silver 5), it would be pretty easy to swap heatsinks at the same time...

The SMBus controller is what allows Windows to monitor and control your hardware -- this could be why it's not controlling the fan speed.   It's the "System Management Bus" controller.  You apparently didn't install the Intel INF update utility - Item #6 here:


Author Comment

ID: 16726701
As per noise of the 9500, I was just going off the reviews off of www.silentpcreview.com.
At top speeds the hyper 48 hits 25 dbA/1m, while the 9500 hits 37 dbA/1m - a bit more than twice as loud (Db don't add like math - every 10db is a doubling of apparent sound.  Makes things a little confusing.)  What I did not compare is cooling power per DB of noise.  What I neglected at previous comparison was the fact that even when running at low speed @22 dbA/1m it still out performs the hyper 48, not by much, but it does.  I plan to order this HSF on monday, if you can put me to rest on one consern - since this fans is blowing parallel to the mobo instead of onto it, will the mobo chips and stuff still get sufficient cooling?

For some reason, the link you provided will not work for me, and the nearest thing I can find is this: http://downloadfinder.intel.com/scripts-df-external/Detail_Desc.aspx?agr=&DwnldID=4841&ProductID=816

This does not make any mention of my chipset, 945G, only the 8xx series.  Should/can I still use this on my board, or is there somthing simillar for the 945 chipset?

Author Comment

ID: 16726721

>"One good thing is that Intel CPU's don't simply shut down at the thermal spec temp -- they will actually continue to work quite well until about 80 °C, at which point they begin a thermal shutdown process.   It's a BAD idea to ever run above 70 °C, however, and you SHOULD never run above the thermal spec -- although in the situation you've described that may be difficult when ambient gets that high."

I actually forgot to remove the plastic protector on the bottom of the HSF when I first installed it.  I couldn't figur out why I was hiiting temps of 80-90C!!!!  I hope I didn't damage anything.  Even at these temps, the fan refused to kick into high speed.  I didn't notice any thermal shutdown either.

Author Comment

ID: 16726728
The links from Silent PC are as follows in case you want to see them:


Zalman 9500
LVL 70

Expert Comment

by:Gary Case
ID: 16726796
Interesting results in Silent PC's review -- I've skimmed these before, but don't remember them being so negative on noise levels.   Note that (regarding the 9500) they DO say "... At roughly the same airflow it significantly outperforms every other heatsink we've tested."

I also note that they show a noise level of 37dB (I'm well aware of how to measure noise levels, by the way), although Zalman's specs show 27.5dB at max fan speed.   Not sure why the discrepancy -- but they also show a 39dB level for a 7000 (!!), which is absolutely NOT consistent with the noise level I get from mine !!   I don't know why the discrepancy -- I'm not discounting the SilentPC review, but I do have to wonder if they got a bad unit; or if they weren't using it with the included FanMate (it's actually designed to not be run at a full 12v).

I don't have a 9500 here, but have used one for a friend's PC I built a couple of months ago - and he's absolutely tickled with it's performance; and it is NOT noisy.   I don't know what else to say here -- I'm still going to use one => as you noted (and SilentPC said), even if you turn the fan way down it still performs as well or better than the currently available competition.

As for cooling other components -- I'm sure it does as well as any other fan.  The key is air movement across the board -- and air blowing straight down onto the heatsink doesn't move any more air than one blowing sideways.   In fact, the thermodynamics actually favor the sideways air movement -- as there's not an immediate obstruction (the motherboard) with a sideways-mounted fan.

I just clicked on the link to Intel I provided above and it works fine !!  Try it again.   If for some reason it doesn't work (different browser ?? -- I'm using IE) just go to www.intel.com and search for your motherboard (945GNT), then look at the available downloads.

I doubt you damaged your CPU -- but forgetting to remove the plastic protector didn't help anything !!   You must not have dramatically heated the CPU, as it would have simply shut down.   You don't get any warning when it hits thermal shutdown -- it simply stops.

I'd be most interested in feedback on your temps AND your "perceived noise level" after you install a 9500 !!

Author Comment

ID: 16731466
Right now I am doing a test with the hyper 48.  I have had prime95 torture test running for 9 hours in a room that is 30C/90F.  This brings the mobo temp to 55C, the chip to 65C, and the HD to 50C.  Everything is running fine.  No erros in Prime95 yet.

I installed the patch you provided, and it did take care of the SMbus issue in the device manager, but the mobo still refuses to kick the fan into high speed.  Every once in a while it allows the case fan to jump to 1400rpm instead of 650rpm, but it won't even let that happen steady.  it is only high speed for about 30-40% of the time.

What do I have to do to get this mobo to allow the fans to run high speed?  I installed "speed fan" hoping that the mobo would allow me to change the fan speed in that sofware, but no go.  I don't know what to do other than run the fans manually with a fan controller.  Surely the mobo should be capable of such a task.

I am still a might worried what the system will do at 10-20C hotter than this, which is what it moght encounter once installed back into the rack and at the venue I am to record (http://www.churchofgodonline.com/ohio-campmeeting.htm).  Here's hoping!

Please let me know if you have any other suggestions to get the mobo working - should I close the question now and give you the points, or would you rather that I give you the results of the 9500 (I am still debating that issue - I wish I would have purchased that instead of the hyper 48 - I don't need an extra heatsink around)?  As far as I'm concerned you've been more than helpful to say the least.  Thanks a lot!!!
LVL 70

Accepted Solution

Gary Case earned 2000 total points
ID: 16731764
Well ... after 9 hours at full load you're right at the thermal spec of the CPU => it's safe to say it won't get any hotter, but of course that's at a 30 °C ambient temperature.   If you seriously expect the ambient temps to hit 40, then you COULD have a problem ...

HOWEVER ... you're not going to be running Prime95 at the event you're recording.   Recording a stereo soundtrack is a very low CPU usage task -- just for grins I fired up Cool Edit and started a recording to see what it does => on my CPU it runs 2-3% utilization and hasn't raised the temp above the 37 °C it was when I started a few minutes ago.   Assuming you're simply going to be recording (even a multi-track session shouldn't be much more demanding).

I suggest you run a test with the recording program you'll be using -- let it record as many tracks as you plan to record and see what kind of temps you get.   I suspect it will be MUCH lower than the 65 °C you're getting with Prime95 ==> probably in the low 40's.   If so, you'll most likely be fine in Ohio  (I just checked the 10-day forecast for West Milton; and the hottest day projected between now and the 31st is 85°).   So if you're testing the system at 90° and it's only hitting 65°C at 100% CPU you should be FINE.

Have you looked VERY CAREFULLY in the BIOS to see if there are any settings for whether or not to allow fan control?   You may be able to turn off fan speed adjustment -- in which case the fan will run at maximum speed.   Even if speed control is enabled, I'm surprised that at the temps you're seeing it doesn't ramp the fan up to max speed.   I agree that simply doesn't sound right.   If there are any controls in the BIOS, you should either turn them off; or adjust the thermal points where they kick in the fan (some BIOS's allow you to set this).

In any event, I think you could close this question -- I think you have plenty to "chew on" => and can in all likelihood use the system you have with no problems for the recordings you need to make.   The one thing you might want to do is to either add a rack-mounted fan unit, or a free-standing fan that could help circulate air through the rack if you really think the temps are going to get as high as you've suggested.

Even if you close this question, please post back with the results after you're recordings in Ohio.  I'm interested in how the system performs; but as I noted, recording is nowhere near as CPU-intense as the testing you're doing now, so I'm confident you'll be fine.
LVL 70

Expert Comment

by:Gary Case
ID: 16731792
... just took at look at your motherboard's manual ==> it does indeed have fan speed controls that adjust the fan speed and/or switch the fan on/off as needed.  It's not clear from the manual whether or not the BIOS Setup program provides any capability to adjust the parameters of this.   If not, I'd simply be SURE you have the heatsink fan connected to the proper fan connection (for CPU fan), and trust that the board is working correctly.

Author Comment

ID: 16733889
Thanks gary,  I only wish there was a way to grade at A+!  I will be looking into the fan controls a bit deeper to see what I can find.  I am certain however that I have it pluged into the right socket.  I just need to find out if there is a way to change the settings.

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