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How big of an effect does case airflow play on Core Temp?

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November 23, 2007 1:46:51 AM

Short story: I have a Lian Li A08B case. It has one 120mm intake and one 120mm outtake fan. The intake fan has a dust filter which works nicely, but also seems to reduce intake air flow a bit.

Right now my E6850 3.0ghz at stock will idle at around 52C and when I ran the most intensive prime95 (small fft) it will shootup to about 68C. This seems way too high. I've verified the stock HSF is properly seated and I'm out of explanations besides poor airflow, but it doesn't seem THAT bad in my base. I removed the sides of my case and my temperatures were not lowered.

I just ordered the artic cooler 7 freezer pro (or whatever it's called) with the vain hope I could score an overclock to 3.6 ghz with reasonable temps (65C or below). If I try to do 3.6ghz on stock, my temps shoot up to 75C and of course, I stop the testing immediately. Most people running e6850 at stock with stock hsf don't seem to have such high load temps. Can anyone with with the same cpu/case or similar chip in?


Thanks.
November 23, 2007 1:53:50 AM

LOL WHAT? from 52c shooting to 68F?
You have a really warm room a bad hsf or a crappy airflow
November 23, 2007 2:00:45 AM

68C....68C...
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November 23, 2007 2:18:50 AM

Seems a bit high, but not too high that the system will become unstable. The first thing I would do is check to see what Vcore you are running at. If you have it set to auto, the MB usually set voltage quite high at stock settings. My P5B on auto had a Vcore of 1.42 or so when it was set to auto on the stock clock speed.

I have and E6420 @ 3.0 (1.355 Vcore with 8+ hours of Prime 95 stable) and with the stock HSF and my Antec 900 (2 front 120's, one rear 120 and a larger exaust on the top) and my system will idle on average at 33-35 depending on ambiant. At load, it will not increase past 57-58 C. Mind you, after switching to the 900, my core temps dropped 5-7 C on average across the board from a generic no fan case.

Let us know what your Vcore is set at, as that would be my first bet for the higher temps.
November 23, 2007 4:47:27 AM

I have it set on auto, but on auto-voltage according to CPU-Z my CPU actually uses less voltage (1.1-1.2v). If I set my voltage manually to 1.3125 (or whatever the default) is the temperatures stay about the same or actually increase a degree or two under load.

I think perhaps I need to replace my 120mm fans with higher CFM ones, but then the noise level will certainly increase. Also how necessary is that dust filter on the intake?

I opened up the sides of my cases, though, and that didn't improve the coretemp readings at ALL. Maybe the thermal interface material on my stock hsf was fubar?

November 23, 2007 2:21:14 PM

No one else with an e6850 and just average case airflow got coretemp readings for me?
November 23, 2007 2:55:42 PM

I can do a quick test, using TAT. Keep in mind TAT pushes the CPU harder then anything.

I use an E4400 OC to 3ghz. I use a Zalman Fan controller (up to 6 fans), so my front/rear/CPU/Side fans are adjustable. Turning the fans all down, using TAT:

Ambient temp 78F or 26C

Speed Fan
Tcase - 63-64C

CoreTemp
Core0 - 75C
Core1 - 75C

Ran over 5 mins

Fans on Full Speed:

Speed Fan
Tcase - 58C

Core0 - 68-69C
Core1 - 68-69C

Took another 5 mins to get it cooler. Hope that helps.
November 23, 2007 3:16:22 PM

Sorry man, I have an AMD system, but I have been working on a similar problem for about a year.

AMD 5600+ AM2
Biostar Tforce 590 SLI
Sunbeam Silent Storm Case
8800 GTS Video Card

My System has 2 120mm intake fans in the front, a side 120mm intake fan, a 120 mm exhaust fan, and my power supply fan exhausting out of the top back.

My CPU temp problem is now under control actually. It was idling at around 45-50C but it is now down to around 35 to 40. I fixed this problem by making a duct in my spare 5 1/4 drive bays to bring in fresh air directly over my cpu.

My Northbridge idles at about 55C all the time. Nothing I do can change this. The problem I am having is that I have no airflow in the bottom of the case and no way to do so without significant case modification. I have 120mm intake fan on the bottom, but do to poor case design the air never reaches the northbridge, GPU, or Sound Card. I do have crashes due to this temperature issue.

I have tried numerous fans, slot fans, and even reseating all heatsinks with AS5 to try ad combat the heat problem. I am now saving up to buy an antec 900 as there is nothing more I can do to try and save this case.

So to answer in your question, in my experience case air flow is very important to control your temps. Without proper airflow, anythign short of a water cooling system will bea waste of money.
November 23, 2007 3:26:56 PM

Did another test with Orthos (priority 9) since doesn't exactly send the CPU in to over load. :lol: 

Test was over 15mins. Edit: Ambient temps increase after the TAT test. 80-81F or 27C)

Screen cap for over 10 mins with fans all on low:



Screen cap after 15mins with fans all on high:



Did that to show more of a closer realistic CPU usage/heat.
November 23, 2007 5:11:37 PM

7C difference just on fan speed? Maybe I do need more powerful fans and need to remove that dust filter...
November 23, 2007 5:36:14 PM

Heh, well I forgot to mention, I don't use any dust filters. Front fan is 140mm, side, cpu and rear are 120mm.

I figure I'm going to end up dealing with dust anyways. :cry: 
a b à CPUs
November 23, 2007 6:12:23 PM

ericvpi, below is the Scale for your E6850 according to Intel's specifications, as shown in the Core 2 Quad and Duo Temperature Guide: http://www.tomshardware.com/forum/221745-29-core-quad-t...

"...Section 6: Scale

Scale 1: Duo

E6x50: Tcase Max 72c, G0 Stepping, Tjunction Max 100c, Vcore Default 1.350, TDP 65w, Delta 10c

-Tcase/Tjunction-
--70--/--80--80-- Hot
--65--/--75--75-- Warm
--60--/--70--70-- Safe
--25--/--35--35-- Cool..."

You can use Section 9 to calibrate your temperatures so you'll know that they're accurate.

Comp :sol: 
November 23, 2007 6:28:34 PM

Grimmy said:
Heh, well I forgot to mention, I don't use any dust filters. Front fan is 140mm, side, cpu and rear are 120mm.

I figure I'm going to end up dealing with dust anyways. :cry: 



I only have one intake 120mm and one outtake 120mm, and as I said the intake has a dust filter. I don't know the specs of the fans because they came with my computer. Right now at stock my coretemps max under load at about 68C. I wonder what they would be like after I install my arctic cooler freezer 7 pro, but with the same case circulation.

November 23, 2007 6:33:27 PM

Whelp, taking out the filter will increase the airflow. The Freezer Pro should be in line with the rear exhaust, so it should help out even more.

Just play around with it. Take the filter out now and see how it helps. The only real main factor is your ambient temp. My temps on load would be lower if my room was 70F rather.. 78-80F. :cry: 
a c 314 à CPUs
November 23, 2007 6:43:51 PM

@ericvpi: Since your temps with an open case did not go down, it would appear that case cooling airflow is not the problem. If you direct a house fan into the works, do you get the same result?

The stock heat sink is supposed to do an adequate job, but that assumes no overclocking. In my experience, an aftermarket cooler is much better if you are overclocking, or if you want less noise. The thermalright ultra120 extreme is the best one out there right now. Anandtech tests several coolers: http://www.anandtech.com/casecoolingpsus/showdoc.aspx?i...

As I am now typing this, speedfan shows my E6850(stock) with the thermalright at 34c. I used arctic silver 5.
a b à CPUs
November 23, 2007 6:49:48 PM

geofelt, from the Temp Guide above:

"...Section 14: Recommendations

(B) Masscool Shin-Etsu X23 can reduce CPU temps by ~ 4c compared to Arctic Silver 5, which is far more popular than it is effective. The first link shown below is to a very in-depth Thermal Interface Material (TIM) comparison that was posted 2/2/07 on Tom's Overclocking - Cooler and Heatsinks Forum, which was conducted by DaSickNinja. This 6 page thread is very revealing, however, the review has been moved to the second link shown below, Xtreme CPU.

DaClan Review: Thermal Interface Shootout: http://www.tomshardware.com/forum/221751-29-daclan-revi...

Note: Due to Tom's servers forcing asterisks in the link below, when clicked it will cause "This page cannot be displayed". Simply backspace the 3 asterisks and type x-c-p-u-s without hyphens, then press enter.

Thermal Interface Material Comparison: http://www.***.com/forums/case-psu-cooling/3902-thermal-interface-material-comparison.html

Masscool Shin-Etsu X23 Thermal Interface Material (TIM) can reduce CPU temps by ~ 4c compared to Arctic Silver 5, and is simply the best TIM for CPU cooling.

X23 is available at the following sites:

http://www.chillblast.com/product.php?productid=16932
http://www.ajigo-store.com/se7783d.html
http://www.crazypc.com/products/50118.html
http://www.watercoolingshop.com/catalog/product_info.ph...
http://www.specialtech.co.uk/spshop/customer/product.ph... ..."

Comp :sol: 
November 23, 2007 6:50:02 PM

Silverstone TJ09 case here w/ 5 120mm fans, the QX6850 w/ box cooler reads 28 - 35C, superior case imo. I think the huge difference is that the PS is on the bottom of the case away from the CPU not emitting more heat in that area. Considering that heat rises the 2 fans ontop of the case are very effective at removing heat from the case. It's great having a fan strictly for cooling the video card(s) and one for the HD(s). Besides the fact the case is rather huge, more space for working on components and allowing excellent airflow.
November 23, 2007 7:01:35 PM

Thinking about it, 52C idle (just slipped my mind), might just indicate the stock HSF isn't on right.

I basically give this type of advice:

If you using the stock HSF, and it was your first time building a 775 socket, heres a video to watch:

Intel CPU Install

Ever since the 775 socket came out, the 4 push pins on the HSF generally cause over heating problems. In my opinion, the 4 pins just plain suck. The best way to be sure the pins are through, is to take the MB out and look at the backside of the MB:

November 23, 2007 8:02:56 PM

So if it doesn't look like that I need to push the pins harder, right?
November 24, 2007 12:12:38 AM

I think one of those push pins was out. I redid it (and replaced my exhaust fan) and now I max out at 64C instead of 68C and my idle is down from 49 to 38C!
November 24, 2007 1:04:03 AM

Another update after I fixed my hsf: With side cover off will max out at 62C, with case on it will max out at 67C. So 5C can be attributed to poor airflow...
a c 314 à CPUs
November 24, 2007 2:25:09 AM

Good job on fixing the pins; they can be tricky. Was that with the stock cooler? If so, you can look forward to some improvement with an aftermarket cooler.

As to the heat in the case, I will bet you have a fairly hot VGA card; what is it? This can cause all sorts of problems for your cpu if you don't get the vga heat out of the case quickly. Airflow is helped if you did a neat wiring job, so that the air flows through well. It will also help if you can keep your ambient temperature down.
November 24, 2007 4:17:46 AM

Yeah I have a fairly hot GPU. It's an 8800GT single slot. That was stock cooler. It appears fixing my pushpins greatly lowered my idle temps, but not so much my load (only about 3-4C).

I ordered the arctic7 freezer pro and hopefully that will allow me to kick my cpu up to 3.6ghz without going over 65C. My case had bad airflow because it only has one intake fan (120mm) that has a dust filter on the outside.
November 24, 2007 5:09:29 AM

I might have posted this elsewhere, but here's the info on my e6850 @ 3.6 GHz. My case wasn't the best choice, and may be more of an issue than yours, but 3.6 isn't a problem, and the 1.3875v doesn't seem to cause any problems. The reason I avoided Auto for voltages was because non-CPU voltages were unnecessarily high.

November 24, 2007 1:52:02 PM

You have less vdroop than I do, kuni. Cpu-Z for you read 1.33v when you set it to 1.38. For me to get 1.33v in cpu-z I have to set voltage in bios to 1.42!
a c 314 à CPUs
November 24, 2007 6:50:41 PM

The extra heat generated by the 8800gt will be recirculating in your case. That is why I like vga cards with double slot coolers that expel the heated air. To help, perhaps you could replace the 120mm x25mm case fans with ones with higher output. Panaflo makes some 120mm x 38mm case fans with higher cfm output, and not much extra noise.
November 25, 2007 7:59:00 PM


wow...
i also use e4400 NO OC because i dont need to (dont play high ended games)
and my idle temp is 25C and when its 100% using, its temp is 37C
i use asus 80mm cpu cooler running at 1800rpm

i didnt know 1Ghz of Oc makes that difference on temp.. :heink: 
November 25, 2007 10:56:01 PM



Well i had a few heat probs but i stuck a post up about that somewhere!?! I agree with Grimmy Push pin HSF are CRAP i could`nt wait to replace them (pain in da arse) designs.
Scaj i to have a big old case at mo got 5x hard drives and can still park a bus in my JEANTECH APOLLO case Cooling is via 2x 120mm fans 1 Intake infront of HDD cage@1100rpm + 1 @1500rpm top rear, below the 120mm fan on the PSU 1x 80mm@3000rpm cooling(WELL OVER COOLING) HDD`s as the hoties Drive at the mo is 26oC ambient temp is 18oC Have another 80mm in the top of the case but in 2years+of having this case i`ve never used it lol!??

!