Built new computer - CPU fan very loud

[Silicon Spear]

I just build a new computer with the following specs:

Cooler Master Cosmos 1000 Case
Gigabyte AM3 770NB/710SB Mobo
Crucial 2x2GB DDR3 RAM
AMD Phenom X4 945 CPU
WD 1 TB HDD
Sapphire 4890 HD GPU
Corsair 520HX PSU
LG SATA DVD+-RW


My computer was being quite loud, even at idle and nothing overclocked. I ruled out the case fans since it's a fairly quiet case, and ruled out the graphics card after manually tuning down its fan speed to minimum and noticing the computer doesn't any quieter. That left the CPU fan, so I downloaded SpeedFan to check what was going on. Sure enough, it was spinning at over 5k RPM under load.

Well, after I closed some programs, I decided to open one of the case doors for a few minutes to see what would happen. Funny thing happened: the CPU fan dipped under 3k RPM and became fairly quiet! Then I closed the case again and it went back to over 4k RPM right away without any new programs being open, and is still rising.

The CPU temperatures were around the low 40's with the case open, but rose to the mid 40's rather quickly after I closed it.


My options:
-return the case? maybe it's the case's fault for being poorly ventilated
-switch the cpu heatsink/fan?
-somehow install a side fan in the case? though I'm not sure how this would be done
-replace at least one of the fans already in there with a faster one?
-just keep the case open?


It was a case for $200 and got good reviews on Newegg, but maybe it's still a bad case? I mean its 37 lb weight doesn't seem heavy at all for me, but I'm concerned about the ventilation. I googled and found that cases are supposed to be cooler when closed. This is the first computer I built so maybe I did something wrong, I don't know. But this seems really weird, so any advice would be appreciated.

 

[masteryoda34]

Check in your BIOS to see if there are settings regulating the speed of the CPU fan.

 

[Silicon Spear]

Originally posted by: masteryoda34
Check in your BIOS to see if there are settings regulating the speed of the CPU fan.

Well, if the CPU fan speed was forcefully lowered, the CPU would get hot, right? I mean, it crossed the 60's under load when the case was closed WHILE being very loud. So it might be more of a ventilation problem....

I'm actually trying to decide how to make the fans run at about 3k RPM without making the CPU hotter......

I mean, if keeping the case open is normal then I will do it, but since I read that it's not normal, I'm asking for advice. Sorry for bothering you.

 

[Billb2]

Originally posted by: Silicon Spear

I'm actually trying to decide how to make the fans run at about 3k RPM without making the CPU hotter......

Since the CPU fan blows case air through it's cooling fins, the only way to make the case fan cool as well at a lower rpm is to get the air in the case to be cooler. That requires more airflow through the case (to get the hot air out and cool air in).

 

[Silicon Spear]

Originally posted by: Billb2

Originally posted by: Silicon Spear

I'm actually trying to decide how to make the fans run at about 3k RPM without making the CPU hotter......

Since the CPU fan blows case air through it's cooling fins, the only way to make the case fan cool as well at a lower rpm is to get the air in the case to be cooler. That requires more airflow through the case (to get the hot air out and cool air in).

So you recommend buying replacement case fans with a higher CFM?

 

[masteryoda34]

Originally posted by: Silicon Spear

Originally posted by: masteryoda34
Check in your BIOS to see if there are settings regulating the speed of the CPU fan.

Well, if the CPU fan speed was forcefully lowered, the CPU would get hot, right? I mean, it crossed the 60's under load when the case was closed WHILE being very loud. So it might be more of a ventilation problem....

I'm actually trying to decide how to make the fans run at about 3k RPM without making the CPU hotter......

I mean, if keeping the case open is normal then I will do it, but since I read that it's not normal, I'm asking for advice. Sorry for bothering you.

I would try lowering it and then do a full load on the CPU and monitor the temperatures. Let us know what it gets up to.

 

[WildW]

That's not a case I'm familiar with, but from the Coolermaster site it looks like the only way for air to get into the case is through the intake fan on the bottom of the case? Interesting design. . . . (i.e. that sounds dubious to me). Maybe you need better clearance under the case - is it on your desk or sitting on carpet for instance?

Maybe try removing one or two of the 5.25" bay covers to see if airflow inwards is the issue?

 

[Silicon Spear]

Originally posted by: masteryoda34

Originally posted by: Silicon Spear

Originally posted by: masteryoda34
Check in your BIOS to see if there are settings regulating the speed of the CPU fan.

Well, if the CPU fan speed was forcefully lowered, the CPU would get hot, right? I mean, it crossed the 60's under load when the case was closed WHILE being very loud. So it might be more of a ventilation problem....

I'm actually trying to decide how to make the fans run at about 3k RPM without making the CPU hotter......

I mean, if keeping the case open is normal then I will do it, but since I read that it's not normal, I'm asking for advice. Sorry for bothering you.

I would try lowering it and then do a full load on the CPU and monitor the temperatures. Let us know what it gets up to.

The highest I could get the fan and CPU core temperature with 4 instances of CPU burn in running is 6000 RPM and 54 degrees (with GPU idle). How hot can a Phenom II get and still be safe (and last a long time), if I start messing with fan speeds?

Originally posted by: WildW
That's not a case I'm familiar with, but from the Coolermaster site it looks like the only way for air to get into the case is through the intake fan on the bottom of the case? Interesting design. . . . (i.e. that sounds dubious to me). Maybe you need better clearance under the case - is it on your desk or sitting on carpet for instance?

Maybe try removing one or two of the 5.25" bay covers to see if airflow inwards is the issue?

The case is on a wooden floor. I'm pretty sure air flow inwards is an issue since opening the case seems to help a lot. But your comment helped me understand which fan is responsible for going in and which is responsible for going out, thanks. Should I try replacing just the bottom fan with a stronger one? Or adding in an inwards side fan? Or maybe - replacing one of the "out" fans with an "in" fan??

 

[zagood]

Add the hard drive fan.
http://www.coolermaster.com/up.../file1201576880654.pdf

Also make sure all the stock fans are plugged in and spinning...
Bottom fan (intake) :120x120x25 mm x 1
Top fan (exhaust) : 120x120x25 mm fan x 2
Rear fan (exhaust) : 120x120x25 mm x 1

In addition, if you have masses of cables everywhere in your case, that can screw with airflow. Read the sticky and get those organized.

Side intake fan might be a good idea. edit: can't install a side fan in that case unless you cut it

p.s. - replace the stock heatsink too.

 

[Silicon Spear]

Originally posted by: zagood
Add the hard drive fan.
http://www.coolermaster.com/up.../file1201576880654.pdf

Hmm, didn't think that would have much of an effect since it only moves air AROUND the case, but okay.

Originally posted by: zagood
Also make sure all the stock fans are plugged in and spinning...
Bottom fan (intake) :120x120x25 mm x 1
Top fan (exhaust) : 120x120x25 mm fan x 2
Rear fan (exhaust) : 120x120x25 mm x 1

Yep, they're fine; thanks for asking.

Originally posted by: zagood
In addition, if you have masses of cables everywhere in your case, that can screw with airflow. Read the sticky and get those organized.

Whoops, didn't think that would have an effect on my cooling! Thanks!

Originally posted by: zagood
Side intake fan might be a good idea. edit: can't install a side fan in that case unless you cut it

Yeah, hm...

Originally posted by: zagood
p.s. - replace the stock heatsink too.

What's a good replacement heatsink for a quad core AM3 socket? I don't see any AM3 heatsinks on newegg, plus I'm not entirely sure which I should get if I want it to be quiet but powerful. I also was thinking of getting some thermal paste to replace the thermal pad on the stock heatsink, since I read they are more effective.

 

[zagood]

Personal opinion: Megahalems with a Scythe S-FLEX SFF21E (or SFF21F on a fan controller)

Pretty sure AM2/AM2+/AM3 heatsink mounting is all the same.