Fan or no fan?

Cooling Processors quietly

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ck8-04
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Fan or no fan?

Post by ck8-04 » Mon Jun 18, 2007 6:07 pm

I am currently running a C2D E6700 passively with a U120X. My temp. at idle is about 50C and at load, using Intel's TAT for about 10 minutes, is about 70C. The only sources of airflow are an undervolted 120mm Nexus rear exhaust and the fan on the Corsair PSU. Would these temps. affect the longevity of my CPU or should I just leave it alone? The fan I have in mind is the Scythe S-Flex version D (800 RPM). Also, does anyone know if the CPU fan header on the Bad Axe 2 will control 3 pin fans?

tehfire
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Post by tehfire » Mon Jun 18, 2007 7:45 pm

Those temps are pretty high, and putting a fan on it really won't affect the noise coming out. I would recommend either the 800RPM or 1000RPM S-flex fan at 7v. I have 2 800RPM fans running @ 12v and they're a little audible, but putting them at 7v would be a little dangerous I think. Once again, I'd put the 1000RPM model at 7v and it would improve your cooling by leaps and bounds.

...not sure about your second question. For sure the board will power the fan, but I'm not sure if it'll regulate the speed.

murtoz
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Post by murtoz » Mon Jun 18, 2007 7:45 pm

I think the big question is, does the cpu temp stabilise at 70 using tat, or does it keep going up if you run tat longer?
If it stays at 70, i would say you're ok. I've always been told electronic components can stand at least 70 without problems, if not more. Add the fact that TAT seems to get the cpu to higher loads (and temps) than any other stress tool I've seen, and you should be ok.

What happens if you duct the CPU? you could maybe try ducting it to the PSU (providing it is above your motherboard), and ducting the chassis fan so that all the air it exhaust has to flow over the motherboard components.

Aris
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Post by Aris » Mon Jun 18, 2007 7:55 pm

the thing is, any airflow, even if its only a few CFM is 100% more effeciant than just convection alone.

i used to use the nexus fans, but now that spcr figured out that the scythe s-flex 1200rpm is just as quiet, and i can now get it at newegg with all my other computer hardware, its just a perfect fit for me now over nexus.

you put a 1200rpm sflex on that, and undervolt it down, you will not be able to hear it at any distance.

i hooked mine up to one of those zalman controllers that comes free with basically every product they make, and just dialed it down to the point where it will reliably start every time, and for my setup thats more than enough airflow. even with the side of the case off, and my hear right next to the fan, i can barely hear it. the room has to be very quiet and i have to be very close to just barely hear anything from it. so with the case closed up and my room with normal things going on like music or the tv, or hell even the clicks from my keyboard drown out any possible noise i may have from that fan.

cmthomson
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Post by cmthomson » Tue Jun 19, 2007 6:04 pm

70C running TAT is just fine. You don't need to add a fan.

tehfire
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Post by tehfire » Tue Jun 19, 2007 10:15 pm

What temp does C2D start to throttle? It's possible that he's not going over 70C because the processor's throttling...

Usually people run a benchmark that's heavily dependent on clock speed to determine whether the CPU's throttling, though I can't think of a suitible program off the top of my head.

seemingly.random
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Post by seemingly.random » Tue Jun 19, 2007 10:54 pm

Unclear as to whether the question is to replace the rear fan or add another somewhere. I've sampled both fans mentioned and at the same rpm with the Nexus being "quiet", the motor noise (ticks) can be heard from the Scythe 800. The Scythe 1600 seems to have a better (lack of) sound undervolted but this could just be sample variance.

The undervolt details are missing. What happens when the Nexus is allowed to run at full speed - ~1080 rpm? Too loud? Most fans (rear facing) disappear into the background around 900 rpm depending on ambient noise of course.

My gut feeling is that heat will eventually destroy anything. The big question is how much heat and when does it become negligible in terms of lifespan, cost and inconvenient downtime.

Don't have any experience with the Bad Axe 2 bios fan control but if it doesn't do what you want, a Zalman Fanmate can cure just about anything - it just can't be made to vary with conditions without human intervention.

I've thought about controlling a non-HSF with the cpu header but haven't tried yet. The downside could be the possible annoyance of hearing an externally facing fan change rpm constantly if load is changing a lot since most bios's are pretty responsive with cpu fan control. If you attempt this, although counter-intuitive, you should probably get a higher rpm fan plus some kind of resistance control (fanmate, etc) for more leeway with the bios.

s_xero
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Post by s_xero » Wed Jun 20, 2007 1:01 am

10 min. heating by a (almost only) convection-cooled CPU seems a bit (read: FAR TOO) short.
A minumum of 1 hour to stabilize is neccesary, if it was only to settle a stable
temperature for all components of your system.

I bet it's going higher than 70... :oops:

ck8-04
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Post by ck8-04 » Wed Jun 20, 2007 4:41 pm

seemingly.random wrote:Unclear as to whether the question is to replace the rear fan or add another somewhere. I've sampled both fans mentioned and at the same rpm with the Nexus being "quiet", the motor noise (ticks) can be heard from the Scythe 800. The Scythe 1600 seems to have a better (lack of) sound undervolted but this could just be sample variance.

The undervolt details are missing. What happens when the Nexus is allowed to run at full speed - ~1080 rpm? Too loud? Most fans (rear facing) disappear into the background around 900 rpm depending on ambient noise of course.

My gut feeling is that heat will eventually destroy anything. The big question is how much heat and when does it become negligible in terms of lifespan, cost and inconvenient downtime.

Don't have any experience with the Bad Axe 2 bios fan control but if it doesn't do what you want, a Zalman Fanmate can cure just about anything - it just can't be made to vary with conditions without human intervention.

I've thought about controlling a non-HSF with the cpu header but haven't tried yet. The downside could be the possible annoyance of hearing an externally facing fan change rpm constantly if load is changing a lot since most bios's are pretty responsive with cpu fan control. If you attempt this, although counter-intuitive, you should probably get a higher rpm fan plus some kind of resistance control (fanmate, etc) for more leeway with the bios.
My question is whether I should add a fan to my U120X or not and if these temps. will affect the life span of my CPU.

When the Nexus runs at full speed, I can easily hear it. There's no motor noise, but there is a whoosh that's audible. It's controlled by the BX2, and it only runs at full speed when my CPU hits 60C. There's a bit of ambient noise during the day, but at night, most of the ambient noise is coming from my PC.

cmthomson
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Post by cmthomson » Wed Jun 20, 2007 5:45 pm

TAT is the best loading software you will find for a C2D. It exceeds the maximum you would ever see with real programs.

70C with TAT is very good. Your C2D will last >5years with this cooling. Don't add fans; you don't need them.

C2D CPUs start to throttle at around 85C. 70 is a very safe temperature.

Aris
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Post by Aris » Wed Jun 20, 2007 5:54 pm

it really all just depends on where your cpu throttles. if what cmthomson says is true (dont have time to verify right now), and its 85c for that chip, then yeah 70c is fine and you dont need a fan. ultimately the chip will keep itself from overheating and killing itself prematurely by throttling. long as its not throttling your fine.

and i agree, 10min is not long enough. you should hold the stress test from the point it stabalizes in temps, and then for an hour afterwards. if the temp rises within that hour, you start the hour over again at the time when it raised.

If you read SPCR's review of the SFLEX's, they also agree with seemingly's findings. the 800rpm model is crap. but the 1200 model is good. read spcr's fan review for the details. a 1200rpm sflex is just as good as a nexus 120mm fan. they cost about the same. only reason i choose sflex over nexus is cause newegg doesnt sell nexus fans.

ck8-04
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Post by ck8-04 » Wed Jun 20, 2007 8:47 pm

Alright, I need to go to sleep soon, but I will run TAT tomorrow until the temperature stabilizes and post the results.

seemingly.random
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Post by seemingly.random » Thu Jun 21, 2007 5:22 am

ck8-04 wrote:My question is whether I should add a fan to my U120X or not and if these temps. will affect the life span of my CPU.

When the Nexus runs at full speed, I can easily hear it. There's no motor noise, but there is a whoosh that's audible. It's controlled by the BX2, and it only runs at full speed when my CPU hits 60C. There's a bit of ambient noise during the day, but at night, most of the ambient noise is coming from my PC.
Ok, minimal noise is of utmost importance. IMO, 60 at idle is way too high but that's just MO (had to replace most of the parts of a Dell laptop as a result of heat). It depends on the load - if it's going to be anywhere close to TAT then add another fan - one going 5-600rpm is better than none. It looks like the Zalman 9700-NT is 4-pin if you're willing to spend that much.

As far as the BX2 BIOS CPU 3-pin fan control question, there's a three pin fan in the case now - the Nexus. Just try it for a couple of minutes. The worst that could happen is that it will only run at full speed if the BIOS is only looking at the PWM pin for feedback (check BIOS options).

Don't know how a fan is attached to the U120X but remember that the Nexus must be hacked for clips.

What are your HD temps?

ck8-04
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Post by ck8-04 » Thu Jun 21, 2007 12:30 pm

I didn't run TAT for the full hour and ran it for half an hour instead. The temps seemed to stabilize at about 80C and 78C for cores 0 and 1, respectively.

The U120X uses the same clips that the U120 uses to attach a fan and, yes, a Nexus must be modified to use the clips.

HD temp is 56C according to Speedfan.

seemingly.random
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Post by seemingly.random » Thu Jun 21, 2007 1:57 pm

ck8-04 wrote:HD temp is 56C according to Speedfan.
Ouch. Some would say this is just fine but IMO this is playing with fire... I get uncomfortable (rightly or wrongly) with an HD temp > 40c. What average temp does Speedfan report with the SMART "in-depth online analysis"? It's 36 for a WD320AAKS. I recently moved this drive to the upper chamber in an NSK3300 for cleaner wiring mgmt. Temp is 40 at night and 43 during the day. If I can't get the daytime temp down I'll probably move it back to the lower chamber where it was 35.

I don't think others meant that TAT should be run for exactly an hour. It should be run until temps stabilize (how ever long this takes) and then a little longer to make sure.

ck8-04
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Post by ck8-04 » Thu Jun 21, 2007 7:46 pm

It's 36 for a Raptor as well.

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